I have some code that goes through a range (for example, D1:H10) and for
every 3rd row, it highlights D3:H3, copies it and then moves up one row to D2
and paste specials the value. I'm trying to alter a piece of code I used to
insert the formula in the same cell range that I am copying and pasting, but
I'm missing how to prevent it from not selecting every 3rd row in the range
as it loops.

Here's the code:
-----Begin Code-----
Dim ColsSelection
Dim RowsSelection
Dim RowsBetween
Dim Diff
Dim FinalRange
Dim xCell

Range("D1:H10").Select
ColsSelection = Selection.Columns.Count
RowsSelection = Selection.Rows.Count
RowsBetween = 3
Diff = Selection.Row - 1
Selection.Resize(RowsSelection, 1).Select
Set FinalRange = Selection. _
Offset(RowsBetween - 1, 0).Resize(1, ColsSelection)
For Each xCell In Selection
If xCell.Row Mod RowsBetween = Diff Then
Set FinalRange = Application.Union _
(FinalRange, xCell.Resize(1, ColsSelection))
FinalRange.Select
Selection.Copy
ActiveCell.Offset(-1, 0).Select
Selection.PasteSpecial Paste:=xlPasteValues
Application.CutCopyMode = False
Selection.NumberFormat = "0"
End If
Next xCell
Range("A2").Activate

End Sub
-----End Code-----

Specifically, this piece to the code:

Set FinalRange = Application.Union(FinalRange, xCell.Resize(1, ColsSelection))

Tells it to keep adding to the selected range, but I don't want it to keep
adding to the selected range. I want it to move down 4 rows and then select
D6:H6 and copy and paste special value again. I tried commenting out the
Union code, but then it keeps selecting D3:H3 through each loop. Any
suggestions as to how I can get it to stop adding to the selected range?

Thanks for any help.