diff --git a/moving_average_series.go b/moving_average_series.go
index ad5535c..2fe075a 100644
--- a/moving_average_series.go
+++ b/moving_average_series.go
@@ -42,7 +42,7 @@ func (mas *MovingAverageSeries) GetValue(index int) (x float64, y float64) {
 	if mas.InnerSeries == nil {
 		return
 	}
-	if mas.valueBuffer == nil {
+	if mas.valueBuffer == nil || index == 0 {
 		mas.valueBuffer = NewRingBufferWithCapacity(mas.GetWindowSize())
 	}
 	if mas.valueBuffer.Len() >= mas.GetWindowSize() {
@@ -63,7 +63,7 @@ func (mas MovingAverageSeries) GetLastValue() (x float64, y float64) {
 	}
 	windowSize := mas.GetWindowSize()
 	seriesLength := mas.InnerSeries.Len()
-	startAt := seriesLength - (windowSize + 1)
+	startAt := seriesLength - windowSize
 	if startAt < 0 {
 		startAt = 0
 	}
diff --git a/moving_average_series_test.go b/moving_average_series_test.go
index 2127439..9996bcd 100644
--- a/moving_average_series_test.go
+++ b/moving_average_series_test.go
@@ -52,7 +52,7 @@ func TestMovingAverageSeriesGetValue(t *testing.T) {
 	assert.Equal(6.0, yvalues[8])
 }
 
-func TestMovingAverageSeriesGetLastValue(t *testing.T) {
+func TestMovingAverageSeriesGetLastValueWindowOverlap(t *testing.T) {
 	assert := assert.New(t)
 
 	mockSeries := mockValueProvider{
@@ -63,10 +63,29 @@ func TestMovingAverageSeriesGetLastValue(t *testing.T) {
 
 	mas := &MovingAverageSeries{
 		InnerSeries: mockSeries,
-		WindowSize:  10,
+		WindowSize:  15,
 	}
 
 	lx, ly := mas.GetLastValue()
 	assert.Equal(10.0, lx)
 	assert.Equal(5.5, ly)
 }
+
+func TestMovingAverageSeriesGetLastValue(t *testing.T) {
+	assert := assert.New(t)
+
+	mockSeries := mockValueProvider{
+		Seq(1.0, 100.0),
+		Seq(100, 1.0),
+	}
+	assert.Equal(100, mockSeries.Len())
+
+	mas := &MovingAverageSeries{
+		InnerSeries: mockSeries,
+		WindowSize:  10,
+	}
+
+	lx, ly := mas.GetLastValue()
+	assert.Equal(100.0, lx)
+	assert.Equal(5.5, ly)
+}
diff --git a/testserver/main.go b/testserver/main.go
index 68bcae2..43856d3 100644
--- a/testserver/main.go
+++ b/testserver/main.go
@@ -45,6 +45,49 @@ func chartHandler(rc *web.RequestContext) web.ControllerResult {
 		},
 	}
 
+	s1lv := chart.AnnotationSeries{
+		Name: fmt.Sprintf("Last Value"),
+		Style: chart.Style{
+			Show:        true,
+			StrokeColor: chart.GetDefaultSeriesStrokeColor(0),
+		},
+		Annotations: []chart.Annotation{
+			chart.Annotation{
+				X:     float64(s1x[len(s1x)-1].Unix()),
+				Y:     s1y[len(s1y)-1],
+				Label: fmt.Sprintf("%s - %s", "test", chart.FloatValueFormatter(s1y[len(s1y)-1])),
+			},
+		},
+	}
+
+	s1ma := &chart.MovingAverageSeries{
+		Name: "Average",
+		Style: chart.Style{
+			Show:            true,
+			StrokeColor:     drawing.ColorRed,
+			StrokeDashArray: []float64{5, 1, 1},
+		},
+		WindowSize:  10,
+		InnerSeries: s1,
+	}
+
+	s1malx, s1maly := s1ma.GetLastValue()
+
+	s1malv := chart.AnnotationSeries{
+		Name: fmt.Sprintf("Last Value"),
+		Style: chart.Style{
+			Show:        true,
+			StrokeColor: drawing.ColorRed,
+		},
+		Annotations: []chart.Annotation{
+			chart.Annotation{
+				X:     s1malx,
+				Y:     s1maly,
+				Label: fmt.Sprintf("%s - %s", "test", chart.FloatValueFormatter(s1maly)),
+			},
+		},
+	}
+
 	c := chart.Chart{
 		Title: "A Test Chart",
 		TitleStyle: chart.Style{
@@ -76,30 +119,9 @@ func chartHandler(rc *web.RequestContext) web.ControllerResult {
 		},
 		Series: []chart.Series{
 			s1,
-			&chart.MovingAverageSeries{
-				Name: "Average",
-				Style: chart.Style{
-					Show:            true,
-					StrokeColor:     drawing.ColorRed,
-					StrokeDashArray: []float64{5, 1, 1},
-				},
-				WindowSize:  10,
-				InnerSeries: s1,
-			},
-			chart.AnnotationSeries{
-				Name: fmt.Sprintf("Last Value"),
-				Style: chart.Style{
-					Show:        true,
-					StrokeColor: chart.GetDefaultSeriesStrokeColor(0),
-				},
-				Annotations: []chart.Annotation{
-					chart.Annotation{
-						X:     float64(s1x[len(s1x)-1].Unix()),
-						Y:     s1y[len(s1y)-1],
-						Label: fmt.Sprintf("%s - %s", "test", chart.FloatValueFormatter(s1y[len(s1y)-1])),
-					},
-				},
-			},
+			s1ma,
+			s1lv,
+			s1malv,
 		},
 	}