I think this should be done with a combination of style and macro.
If you customised a style in your document to provide the 'Unit #' as an autonumber and include the "new page" setting then the macro could be as simple as
Code:
Sub AddPages()
Dim iNum As Integer
iNum = Val(InputBox("How many units are you adding?", , 5))
If iNum > 0 Then
Selection.Style = "Heading 1"
Selection.TypeText String(iNum, vbCr)
End If
End Sub