XY Plot With Macro

In the attached sheet I have data in column F and G which I am plotting using the following

Sub evmplot()
Dim i As Integer
ThisWorkbook.Worksheets("sheet1").Activate
ActiveSheet.ChartObjects("EVM").Activate
ActiveChart.ChartArea.Select
For i = 1 To 15
ActiveChart.SeriesCollection.NewSeries
ActiveChart.SeriesCollection(i).XValues = "=sheet1!R[" & 5 + (i - 1) * 13 & "]C6:R[" & 17 + (i - 1) * 13 & "]C6"
ActiveChart.SeriesCollection(i).Values = "=sheet1!R[" & 5 + (i - 1) * 13 & "]C7:R[" & 17 + (i - 1) * 13 & "]C7"
Next i
End Sub

when I =1 , the sereis should be from R5c6:R17C6. But the first series in the plot is from R6C6:R18c6. Same is the case with other series also.