Exactly guys Thanks a lot i resolved it with
Sub Loop8()
' This loop does the calculating itself and writes the result into each
cell
Range("D1").Select
Do

If IsEmpty(ActiveCell.Offset(0, -1)) Then
ActiveCell.Value = 0
ActiveCell.Offset(0, -1).Value = "Customer"

ElseIf ActiveCell.Row = "1" Then
ActiveCell.Value = ActiveCell.Offset(0, -2).Value -
ActiveCell.Offset(0, -3).Value


ElseIf ActiveCell.Offset(0, -1).Value = ActiveCell.Offset(-1, -1)
Then
ActiveCell.Value = 0

Else
ActiveCell.Value = ActiveCell.Offset(0, -2).Value -
ActiveCell.Offset(-1, -2).Value
End If
ActiveCell.Offset(1, 0).Select
Loop Until IsEmpty(ActiveCell.Offset(0, -2))



End Sub