diff --git a/lib/grade/grade_category.php b/lib/grade/grade_category.php
index 190ab09b12c..d5a9e6d72fa 100644
--- a/lib/grade/grade_category.php
+++ b/lib/grade/grade_category.php
@@ -967,10 +967,20 @@ class grade_category extends grade_object {
      *
      * @return bool True if extra credit used
      */
-    function is_extracredit_used() {
-        return ($this->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN2
-             or $this->aggregation == GRADE_AGGREGATE_EXTRACREDIT_MEAN
-             or $this->aggregation == GRADE_AGGREGATE_SUM);
+    public function is_extracredit_used() {
+        return self::aggregation_uses_extracredit($this->aggregation);
+    }
+
+    /**
+     * Returns true if aggregation passed is using extracredit.
+     *
+     * @param int $aggregation Aggregation const.
+     * @return bool True if extra credit used
+     */
+    public static function aggregation_uses_extracredit($aggregation) {
+        return ($aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN2
+             or $aggregation == GRADE_AGGREGATE_EXTRACREDIT_MEAN
+             or $aggregation == GRADE_AGGREGATE_SUM);
     }
 
     /**
@@ -979,10 +989,21 @@ class grade_category extends grade_object {
      * @return bool True if an aggregation coefficient is being used
      */
     public function is_aggregationcoef_used() {
-        return ($this->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN
-             or $this->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN2
-             or $this->aggregation == GRADE_AGGREGATE_EXTRACREDIT_MEAN
-             or $this->aggregation == GRADE_AGGREGATE_SUM);
+        return self::aggregation_uses_aggregationcoef($this->aggregation);
+
+    }
+
+    /**
+     * Returns true if aggregation uses aggregationcoef
+     *
+     * @param int $aggregation Aggregation const.
+     * @return bool True if an aggregation coefficient is being used
+     */
+    public static function aggregation_uses_aggregationcoef($aggregation) {
+        return ($aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN
+             or $aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN2
+             or $aggregation == GRADE_AGGREGATE_EXTRACREDIT_MEAN
+             or $aggregation == GRADE_AGGREGATE_SUM);
 
     }
 
@@ -1573,14 +1594,14 @@ class grade_category extends grade_object {
 
             //weight and extra credit share a column :( Would like a default of 1 for weight and 0 for extra credit
             //Flip from the default of 0 to 1 (or vice versa) if ALL items in the category are still set to the old default.
-            if ($params->aggregation==GRADE_AGGREGATE_WEIGHTED_MEAN || $params->aggregation==GRADE_AGGREGATE_EXTRACREDIT_MEAN) {
+            if (self::aggregation_uses_aggregationcoef($params->aggregation)) {
                 $sql = $defaultaggregationcoef = null;
 
-                if ($params->aggregation==GRADE_AGGREGATE_WEIGHTED_MEAN) {
+                if (!self::aggregation_uses_extracredit($params->aggregation)) {
                     //if all items in this category have aggregation coefficient of 0 we can change it to 1 ie evenly weighted
                     $sql = "select count(id) from {grade_items} where categoryid=:categoryid and aggregationcoef!=0";
                     $defaultaggregationcoef = 1;
-                } else if ($params->aggregation==GRADE_AGGREGATE_EXTRACREDIT_MEAN) {
+                } else {
                     //if all items in this category have aggregation coefficient of 1 we can change it to 0 ie no extra credit
                     $sql = "select count(id) from {grade_items} where categoryid=:categoryid and aggregationcoef!=1";
                     $defaultaggregationcoef = 0;
diff --git a/lib/grade/tests/grade_category_test.php b/lib/grade/tests/grade_category_test.php
index d4ce639ee01..5451609a8b3 100644
--- a/lib/grade/tests/grade_category_test.php
+++ b/lib/grade/tests/grade_category_test.php
@@ -41,6 +41,7 @@ class core_grade_category_testcase extends grade_base_testcase {
         $this->sub_test_grade_category_aggregate_grades();
         $this->sub_test_grade_category_apply_limit_rules();
         $this->sub_test_grade_category_is_aggregationcoef_used();
+        $this->sub_test_grade_category_aggregation_uses_aggregationcoef();
         $this->sub_test_grade_category_fetch_course_tree();
         $this->sub_test_grade_category_get_children();
         $this->sub_test_grade_category_load_grade_item();
@@ -67,6 +68,8 @@ class core_grade_category_testcase extends grade_base_testcase {
 
         // Do this last as adding a second course category messes up the data.
         $this->sub_test_grade_category_insert_course_category();
+        $this->sub_test_grade_category_is_extracredit_used();
+        $this->sub_test_grade_category_aggregation_uses_extracredit();
     }
 
     // Adds 3 new grade categories at various depths.
@@ -531,11 +534,43 @@ class core_grade_category_testcase extends grade_base_testcase {
 
     }
 
-    /**
-     * TODO implement
-     */
     protected function sub_test_grade_category_is_aggregationcoef_used() {
+        $category = new grade_category();
+        // Following use aggregationcoef.
+        $category->aggregation = GRADE_AGGREGATE_WEIGHTED_MEAN;
+        $this->assertTrue($category->is_aggregationcoef_used());
+        $category->aggregation = GRADE_AGGREGATE_WEIGHTED_MEAN2;
+        $this->assertTrue($category->is_aggregationcoef_used());
+        $category->aggregation = GRADE_AGGREGATE_EXTRACREDIT_MEAN;
+        $this->assertTrue($category->is_aggregationcoef_used());
+        $category->aggregation = GRADE_AGGREGATE_SUM;
+        $this->assertTrue($category->is_aggregationcoef_used());
 
+        // Following don't use aggregationcoef.
+        $category->aggregation = GRADE_AGGREGATE_MAX;
+        $this->assertFalse($category->is_aggregationcoef_used());
+        $category->aggregation = GRADE_AGGREGATE_MEAN;
+        $this->assertFalse($category->is_aggregationcoef_used());
+        $category->aggregation = GRADE_AGGREGATE_MEDIAN;
+        $this->assertFalse($category->is_aggregationcoef_used());
+        $category->aggregation = GRADE_AGGREGATE_MIN;
+        $this->assertFalse($category->is_aggregationcoef_used());
+        $category->aggregation = GRADE_AGGREGATE_MODE;
+        $this->assertFalse($category->is_aggregationcoef_used());
+    }
+
+    protected function sub_test_grade_category_aggregation_uses_aggregationcoef() {
+
+        $this->assertTrue(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_WEIGHTED_MEAN));
+        $this->assertTrue(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_WEIGHTED_MEAN2));
+        $this->assertTrue(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_EXTRACREDIT_MEAN));
+        $this->assertTrue(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_SUM));
+
+        $this->assertFalse(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_MAX));
+        $this->assertFalse(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_MEAN));
+        $this->assertFalse(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_MEDIAN));
+        $this->assertFalse(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_MIN));
+        $this->assertFalse(grade_category::aggregation_uses_aggregationcoef(GRADE_AGGREGATE_MODE));
     }
 
     protected function sub_test_grade_category_fetch_course_tree() {
@@ -721,4 +756,43 @@ class core_grade_category_testcase extends grade_base_testcase {
         $grade->insert();
         return $grade->rawgrade;
     }
+
+    protected function sub_test_grade_category_is_extracredit_used() {
+        $category = new grade_category();
+        // Following use aggregationcoef.
+        $category->aggregation = GRADE_AGGREGATE_WEIGHTED_MEAN2;
+        $this->assertTrue($category->is_extracredit_used());
+        $category->aggregation = GRADE_AGGREGATE_EXTRACREDIT_MEAN;
+        $this->assertTrue($category->is_extracredit_used());
+        $category->aggregation = GRADE_AGGREGATE_SUM;
+        $this->assertTrue($category->is_extracredit_used());
+
+        // Following don't use aggregationcoef.
+        $category->aggregation = GRADE_AGGREGATE_WEIGHTED_MEAN;
+        $this->assertFalse($category->is_extracredit_used());
+        $category->aggregation = GRADE_AGGREGATE_MAX;
+        $this->assertFalse($category->is_extracredit_used());
+        $category->aggregation = GRADE_AGGREGATE_MEAN;
+        $this->assertFalse($category->is_extracredit_used());
+        $category->aggregation = GRADE_AGGREGATE_MEDIAN;
+        $this->assertFalse($category->is_extracredit_used());
+        $category->aggregation = GRADE_AGGREGATE_MIN;
+        $this->assertFalse($category->is_extracredit_used());
+        $category->aggregation = GRADE_AGGREGATE_MODE;
+        $this->assertFalse($category->is_extracredit_used());
+    }
+
+    protected function sub_test_grade_category_aggregation_uses_extracredit() {
+
+        $this->assertTrue(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_WEIGHTED_MEAN2));
+        $this->assertTrue(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_EXTRACREDIT_MEAN));
+        $this->assertTrue(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_SUM));
+
+        $this->assertFalse(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_WEIGHTED_MEAN));
+        $this->assertFalse(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_MAX));
+        $this->assertFalse(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_MEAN));
+        $this->assertFalse(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_MEDIAN));
+        $this->assertFalse(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_MIN));
+        $this->assertFalse(grade_category::aggregation_uses_extracredit(GRADE_AGGREGATE_MODE));
+    }
 }