diff --git a/common/static/common/templates/gradebook/_gradebook_modal_table.underscore b/common/static/common/templates/gradebook/_gradebook_modal_table.underscore
index a739818e3b..132eba604e 100644
--- a/common/static/common/templates/gradebook/_gradebook_modal_table.underscore
+++ b/common/static/common/templates/gradebook/_gradebook_modal_table.underscore
@@ -36,6 +36,7 @@
           </tbody>
         </table>
       </div>
+      <div class="grade-override-info-container alert alert-info pattern-library-shim" role="alert"></div>
       <div class="grade-override-menu-buttons">
         <button class="btn grade-override-modal-save"><%- strLib.save %></button>
         <button class="btn grade-override-modal-close"><%- strLib.cancel %></button>
diff --git a/lms/djangoapps/grades/api/v1/views.py b/lms/djangoapps/grades/api/v1/views.py
index 98f0b4b758..cc505d7778 100644
--- a/lms/djangoapps/grades/api/v1/views.py
+++ b/lms/djangoapps/grades/api/v1/views.py
@@ -12,6 +12,7 @@ from rest_framework.generics import GenericAPIView
 from rest_framework.pagination import CursorPagination
 from rest_framework.response import Response
 from six import text_type
+from util.date_utils import to_timestamp
 
 from courseware.courses import get_course_with_access
 from edx_rest_framework_extensions import permissions
@@ -22,16 +23,23 @@ from lms.djangoapps.grades.config.waffle import waffle_flags, WRITABLE_GRADEBOOK
 from lms.djangoapps.grades.constants import ScoreDatabaseTableEnum
 from lms.djangoapps.grades.course_data import CourseData
 from lms.djangoapps.grades.course_grade_factory import CourseGradeFactory
+from lms.djangoapps.grades.events import SUBSECTION_GRADE_CALCULATED, subsection_grade_calculated
 from lms.djangoapps.grades.models import PersistentSubsectionGrade, PersistentSubsectionGradeOverride
 from lms.djangoapps.grades.signals import signals
 from lms.djangoapps.grades.subsection_grade import CreateSubsectionGrade
+from lms.djangoapps.grades.tasks import recalculate_subsection_grade_v3
 from opaque_keys import InvalidKeyError
 from opaque_keys.edx.keys import CourseKey, UsageKey
 from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
 from openedx.core.lib.api.authentication import OAuth2AuthenticationAllowInactiveUser
 from openedx.core.lib.api.view_utils import DeveloperErrorViewMixin
 from student.models import CourseEnrollment
-
+from track.event_transaction_utils import (
+    create_new_event_transaction_id,
+    get_event_transaction_id,
+    get_event_transaction_type,
+    set_event_transaction_type
+)
 
 log = logging.getLogger(__name__)
 USER_MODEL = get_user_model()
@@ -767,17 +775,27 @@ class GradebookBulkUpdateView(GradeViewMixin, GenericAPIView):
             grade=subsection_grade_model,
             defaults=self._clean_override_data(override_data),
         )
-        signals.SUBSECTION_OVERRIDE_CHANGED.send(
-            sender=None,
-            user_id=subsection_grade_model.user_id,
-            course_id=text_type(subsection_grade_model.course_id),
-            usage_id=text_type(subsection_grade_model.usage_key),
-            only_if_higher=False,
-            modified=override.modified,
-            score_deleted=False,
-            score_db_table=ScoreDatabaseTableEnum.overrides,
-            force_update_subsections=True,
+
+        set_event_transaction_type(SUBSECTION_GRADE_CALCULATED)
+        create_new_event_transaction_id()
+
+        recalculate_subsection_grade_v3.apply(
+            kwargs=dict(
+                user_id=subsection_grade_model.user_id,
+                anonymous_user_id=None,
+                course_id=text_type(subsection_grade_model.course_id),
+                usage_id=text_type(subsection_grade_model.usage_key),
+                only_if_higher=False,
+                expected_modified_time=to_timestamp(override.modified),
+                score_deleted=False,
+                event_transaction_id=unicode(get_event_transaction_id()),
+                event_transaction_type=unicode(get_event_transaction_type()),
+                score_db_table=ScoreDatabaseTableEnum.overrides,
+                force_update_subsections=True,
+            )
         )
+        # Emit events to let our tracking system to know we updated subsection grade
+        subsection_grade_calculated(subsection_grade_model)
 
     def _clean_override_data(self, override_data):
         """
diff --git a/lms/djangoapps/grades/docs/decisions/0001-gradebook-api.rst b/lms/djangoapps/grades/docs/decisions/0001-gradebook-api.rst
index 9b930c4865..39db22d19e 100644
--- a/lms/djangoapps/grades/docs/decisions/0001-gradebook-api.rst
+++ b/lms/djangoapps/grades/docs/decisions/0001-gradebook-api.rst
@@ -71,11 +71,18 @@ Decisions
 
    d. A status code of ``422`` will be returned for requests that contain any failed item.  This allows a client
       to easily tell if any item in their request payload was problematic and needs special handling.  If all
-      requested items succeed, a ``202 (accepted)`` is returned.  This status code was chosen because an
-      asynchronous celery task is enqueued for each subsection grade that needs to be updated.
+      requested items succeed, a ``202 (accepted)`` is returned.  This status code was chosen because a
+      celery task is enqueued and waited for each subsection grade that needs to be updated.
 
-   e. We have to thread a ``force_update_subsections`` keyword argument through the Django signal invocation
-      that enqueues the subsection update task.  This is because we may be creating a new subsection grade
-      with no score data available from either ``courseware.StudentModule`` records or from the `Submissions` API.
-      In this case, the only score data available exists in the grade override record, and the subsection ``update()``
-      call should be forced to read from this record.
+   e. We have to thread a ``force_update_subsections`` keyword argument into the subsection update task that
+      we enqueue.  This is because we may be creating a new subsection grade with no score data available from 
+      either ``courseware.StudentModule`` records or from the `Submissions` API. In this case, the only score
+      data available exists in the grade override record, and the subsection ``update()`` call should be forced
+      to read from this record.
+
+   f. We have to synchronously update each grade record for each user in this endpoint. This means the request
+      will be left open for longer period than we wanted. The reason is: the primary consumer gradebook UI
+      would need to display the updated grade result for all users, after update is complete. If we do update
+      asynchronously, the gradebook UI do not know how to update the table with new values, including agregations
+      for the user's course grade. This is the lowest effort change to address the UI display problem. We will
+      need to improve this mechanism as we continue to develop.
diff --git a/lms/static/js/writable_gradebook.js b/lms/static/js/writable_gradebook.js
index db4d9b840e..bc41ab3aa1 100644
--- a/lms/static/js/writable_gradebook.js
+++ b/lms/static/js/writable_gradebook.js
@@ -16,26 +16,21 @@ function _templateLoader(templateName, staticPath, callback, errorCallback) {
 }
 
 function courseXblockUpdater(courseID, dataToSend, visibilityData, callback, errorCallback) {
-    var cleanData = {'users' : {}};
-
-    if (dataToSend instanceof Array)
-        for (var i = 0; i < dataToSend.length; i++) {
-            cleanData.users['id_' + dataToSend.userID] = {
-                'block_id' : dataToSend[i].blockID || '',
-                'grade' : dataToSend[i].grade || '',
-                'max_grade' : dataToSend[i].maxGrade || null,
-                'state' :  dataToSend[i].state || '{}',
-                'user_id' : dataToSend[i].userID || ''
-            };
-        }
-    else if (dataToSend instanceof Object)
-        cleanData.users = dataToSend;
-
-    var postUrl = '/api/score/courses/' + courseID;
-
-    if (!_.isEmpty(visibilityData))
-        cleanData.visibility = visibilityData;
+    var cleanData = _.map(dataToSend, function (data) {
+        return {
+            user_id: data.user_id,
+            usage_id: data.block_id,
+            grade: {
+                earned_all_override: data.grade || 0,
+                possible_all_override: data.max_grade || 0,
+                earned_graded_override: data.grade || 0,
+                possible_graded_override: data.max_grade || 0
+            }
+        };
+    });
 
+    var postUrl = '/api/grades/v1/gradebook/' + courseID + '/bulk-update';
+    $('')
     $.ajax({
         url: postUrl,
         method: 'POST',
@@ -314,6 +309,7 @@ $(document).ready(function() {
         isManualGrading = JSON.parse($(gradeOverrideObject).attr('data-manual-grading'));
         $modal.find('.assignment-name-placeholder').text(assignmentName);
         $modal.find('.block-id-placeholder').text(blockID);
+        $modal.find('.grade-override-info-container').hide();
         if ( _.isEmpty(userAutoGrades) ) {
             $tableWrapper.hide();
             $manualGradeVisibilityWrapper.toggle(false);
@@ -486,6 +482,18 @@ $(document).ready(function() {
         });
     }
 
+    function setInfoMessage(messageText){
+        var $messageField = $('.grade-override-modal').find('.grade-override-info-container');
+        if(messageText) {
+            $messageField.text(messageText);
+            $messageField.show();
+        }
+        else {
+            $messageField.empty();
+            $messageField.hide();
+        }
+    }
+
     $(document).on('click', '.grade-override-modal-save', function() {
         var visibilityData = {};
         if (isManualGrading) {
@@ -499,12 +507,14 @@ $(document).ready(function() {
             return;
         var validStatus = ValidateAdjustedGradesData();
         if (validStatus) {
+            setInfoMessage(gettext('Update in progress, please wait...'));
             courseXblockUpdater(
                 courseID,
                 adjustedGradesData,
                 visibilityData,
                 function(data){
                     gradebookOverrideModalReset();
+                    setInfoMessage();
                     renderAllGradebook = false;
                     gradeBookData = [];
                     $gradesTableWrapper.empty();
diff --git a/lms/static/sass/course/instructor/_writable_gradebook.scss b/lms/static/sass/course/instructor/_writable_gradebook.scss
index d3c7be5ead..a95130af61 100644
--- a/lms/static/sass/course/instructor/_writable_gradebook.scss
+++ b/lms/static/sass/course/instructor/_writable_gradebook.scss
@@ -74,6 +74,10 @@
             .grade-override-menu-buttons {
                 padding: 10px;
             }
+            .grade-override-info-container{
+                margin: 10px;
+                font-size: $small-font-size;
+            }
         }
     }