The original suggestion did not distinguish between actual and forcast rows, it just combined them with the assumption that there would only be 2 rows and it didn't really matter if forcast or actual was first.
To accommodate the new scenarios a helper column is used to identify the actual rows.
Have used column 30 which is "AD" but you can easily adjust it if that's an issue.
This helper column is cleared at the end of the macro.
Row 1 merged cells for Actual and Current Fcst
must be correct as it's the merged columns of Actual that things are based on.
Also now it does matter that the forcast row(s) precede the actual row.
Give this a try
Code:
Sub CombineData_v2()
Dim i As Long, lr As Long
Dim actCount As Long, helpCol As Long
Application.ScreenUpdating = False
With Sheets("Vendor Report")
lr = .Range("S" & Rows.Count).End(xlUp).Row
actCount = .Range("F1").MergeArea.Columns.Count
helpCol = 30 'column 30 is column "AD"
'determine if actual and identify in helpCol
For i = lr To 3 Step -1
If Application.Sum(.Range(Cells(i, 6), Cells(i, 6 + actCount))) > 0 And _
Application.Sum(.Range(Cells(i, 6 + actCount + 1), Cells(i, 17))) = 0 Then
.Cells(i, helpCol) = "A"
End If
Next i
'loop again and only deal with actual rows
For i = lr To 3 Step -1
If .Cells(i, helpCol) = "A" Then
If .Cells(i, "S") = .Cells(i - 1, "S") Then 'Dept-Account-Vendor match
'copy actual to forcast
.Cells(i - 1, "F").Resize(, actCount).Value = .Cells(i, "F").Resize(, actCount).Value
'remove the actual row
.Rows(i).Delete
End If
End If
Next i
'remove helper column
.Columns(helpCol).ClearContents
End With
Application.ScreenUpdating = True
End Sub