diff --git a/mdata/aggmetric.go b/mdata/aggmetric.go
index 2d453f5ef4..a7a4926b47 100644
--- a/mdata/aggmetric.go
+++ b/mdata/aggmetric.go
@@ -436,7 +436,8 @@ func (a *AggMetric) Add(ts uint32, val float64) {
 	} else {
 		// write through reorder buffer
 		res, accepted := a.rob.Add(ts, val)
-		if accepted {
+
+		if len(res) == 0 && accepted {
 			a.lastWrite = uint32(time.Now().Unix())
 		}
 
diff --git a/mdata/reorder_buffer_test.go b/mdata/reorder_buffer_test.go
index 68362ff497..68d7d91fe5 100644
--- a/mdata/reorder_buffer_test.go
+++ b/mdata/reorder_buffer_test.go
@@ -7,18 +7,27 @@ import (
 	"gopkg.in/raintank/schema.v1"
 )
 
-func testAddAndGet(t *testing.T, reorderWindow uint32, testData, expectedData []schema.Point, expectAddFail, expectReordered uint32) []schema.Point {
+func testAddAndGet(t *testing.T, reorderWindow uint32, testData, expectedData []schema.Point, expectAdded, expectAddFail, expectReordered uint32) []schema.Point {
 	var flushed []schema.Point
 	b := NewReorderBuffer(reorderWindow, 1)
 	metricsTooOld.SetUint32(0)
 	metricsReordered.SetUint32(0)
+	addedCount := uint32(0)
 	for _, point := range testData {
-		addRes := b.Add(point.Ts, point.Val)
+		addRes, accepted := b.Add(point.Ts, point.Val)
 		flushed = append(flushed, addRes...)
+		if accepted {
+			addedCount++
+		}
 	}
 	if expectAddFail != metricsTooOld.Peek() {
 		t.Fatalf("Expected %d failures, but had %d", expectAddFail, metricsTooOld.Peek())
 	}
+
+	if expectAdded != addedCount {
+		t.Fatalf("Expected %d accepted datapoints, but had %d", expectAdded, addedCount)
+	}
+
 	if metricsReordered.Peek() != expectReordered {
 		t.Fatalf("Expected %d metrics to get reordered, but had %d", expectReordered, metricsReordered.Peek())
 	}
@@ -95,7 +104,7 @@ func TestReorderBufferAddAndGetInOrder(t *testing.T) {
 		{Ts: 1002, Val: 200},
 		{Ts: 1003, Val: 300},
 	}
-	testAddAndGet(t, 600, testData, expectedData, 0, 0)
+	testAddAndGet(t, 600, testData, expectedData, 3, 0, 0)
 }
 
 func TestReorderBufferAddAndGetInReverseOrderOutOfWindow(t *testing.T) {
@@ -107,7 +116,7 @@ func TestReorderBufferAddAndGetInReverseOrderOutOfWindow(t *testing.T) {
 	expectedData := []schema.Point{
 		{Ts: 1003, Val: 300},
 	}
-	testAddAndGet(t, 1, testData, expectedData, 2, 0)
+	testAddAndGet(t, 1, testData, expectedData, 1, 2, 0)
 }
 
 func TestReorderBufferAddAndGetOutOfOrderInsideWindow(t *testing.T) {
@@ -133,7 +142,7 @@ func TestReorderBufferAddAndGetOutOfOrderInsideWindow(t *testing.T) {
 		{Ts: 1008, Val: 800},
 		{Ts: 1009, Val: 900},
 	}
-	testAddAndGet(t, 600, testData, expectedData, 0, 2)
+	testAddAndGet(t, 600, testData, expectedData, 9, 0, 2)
 }
 
 func TestReorderBufferAddAndGetOutOfOrderInsideWindowAsFirstPoint(t *testing.T) {
@@ -159,13 +168,13 @@ func TestReorderBufferAddAndGetOutOfOrderInsideWindowAsFirstPoint(t *testing.T)
 		{Ts: 1008, Val: 800},
 		{Ts: 1009, Val: 900},
 	}
-	testAddAndGet(t, 600, testData, expectedData, 0, 3)
+	testAddAndGet(t, 600, testData, expectedData, 9, 0, 3)
 }
 
 func TestReorderBufferOmitFlushIfNotEnoughData(t *testing.T) {
 	b := NewReorderBuffer(9, 1)
 	for i := uint32(1); i < 10; i++ {
-		flushed := b.Add(i, float64(i*100))
+		flushed, _ := b.Add(i, float64(i*100))
 		if len(flushed) > 0 {
 			t.Fatalf("Expected no data to get flushed out")
 		}
@@ -197,7 +206,7 @@ func TestReorderBufferAddAndGetOutOfOrderOutOfWindow(t *testing.T) {
 		{Ts: 1003, Val: 300},
 		{Ts: 1004, Val: 400},
 	}
-	flushedData := testAddAndGet(t, 5, testData, expectedData, 1, 2)
+	flushedData := testAddAndGet(t, 5, testData, expectedData, 8, 1, 2)
 	if !reflect.DeepEqual(flushedData, expectedFlushedData) {
 		t.Fatalf("Flushed data does not match expected flushed data:\n%+v\n%+v", flushedData, expectedFlushedData)
 	}
@@ -208,8 +217,8 @@ func TestReorderBufferFlushSortedData(t *testing.T) {
 	buf := NewReorderBuffer(600, 1)
 	metricsTooOld.SetUint32(0)
 	for i := 1100; i < 2100; i++ {
-		flushed := buf.Add(uint32(i), float64(i))
-		if metricsTooOld.Peek() != 0 {
+		flushed, accepted := buf.Add(uint32(i), float64(i))
+		if metricsTooOld.Peek() != 0 || !accepted {
 			t.Fatalf("Adding failed")
 		}
 		results = append(results, flushed...)
@@ -238,8 +247,8 @@ func TestReorderBufferFlushUnsortedData1(t *testing.T) {
 	failedCount := 0
 	metricsTooOld.SetUint32(0)
 	for _, p := range data {
-		flushed := buf.Add(p.Ts, p.Val)
-		if metricsTooOld.Peek() != 0 {
+		flushed, accepted := buf.Add(p.Ts, p.Val)
+		if metricsTooOld.Peek() != 0 || !accepted {
 			failedCount++
 			metricsTooOld.SetUint32(0)
 		} else {
@@ -272,7 +281,7 @@ func TestReorderBufferFlushUnsortedData2(t *testing.T) {
 	}
 	unsortedData := unsort(data, 10)
 	for i := 0; i < len(data); i++ {
-		flushed := buf.Add(unsortedData[i].Ts, unsortedData[i].Val)
+		flushed, _ := buf.Add(unsortedData[i].Ts, unsortedData[i].Val)
 		results = append(results, flushed...)
 	}
 	for i := 0; i < 400; i++ {