Sum of all Loops - VBA

Hello,
I have a program that identifies a product that is being used. If the conditions are met, then it will take the unit cost of each component of the finished good and adds it up and adds it to the finished good - giving the Finished Good it's respective unit cost.
I'm having a problem adding up the values of the components. How do I get the sum of all of the loops? Here's the code, I included comments on the relevant code:

Option Explicit

Sub Invo()
Dim InvAllocWS As Worksheet
Dim BillMatWS As Worksheet
Dim ItemMas As Worksheet
Dim WorkProWS As Worksheet
Dim Wk  As Range, BM  As Range, XX As Range, count As Long, YU As Integer
Dim Dub As Integer


   Set InvAllocWS = Worksheets("Inventory Allocation")
   Set ItemMas = Worksheets("Item Master")
   Set BillMatWS = Worksheets("Bill of Material")
   Set WorkProWS = Worksheets("Work in Process")

   With WorkProWS
      For Each Wk In Range(.Cells(3, 4), .Cells(Rows.count, 4).End(3))
         If (Wk.Cells(1, 9) = "Yes") Then
         Else
           ' Wk.Cells(1, 9) = "Yes"
            If (Wk.Cells(1, 6) = "Yes") Then
               With InvAllocWS
                  For Each BM In Range(.Cells(3, 1), .Cells(Rows.count, 1).End(3))
                     If (BM = Wk) Then
                        With ItemMas
                           For Each XX In Range(.Cells(3, 4), .Cells(Rows.count, 4).End(3))
                              If (XX = BM.Cells(1, 4)) Then
                                 XX.Offset(0, 11) = XX.Offset(0, 11).Value - BM.Offset(0, 4).Value
                                 YU = BM.Offset(0, 9) ' Here is the problem code
    ' I want to find the sum of YU and add it to XX.Offset(0, 14)
                              End If
                           Next
                        End With
                     End If
                  Next
               End With
            ElseIf (Wk.Cells(1, 6) = "Partial") Then
               With InvAllocWS
                  For Each BM In Range(.Cells(3, 1), .Cells(Rows.count, 1).End(3))
                     If (BM = Wk) Then
                        With ItemMas
                           For Each XX In Range(.Cells(3, 4), .Cells(Rows.count, 4).End(3))
                              If (XX = BM.Cells(1, 4)) Then
                                 XX.Offset(0, 11) = XX.Offset(0, 11) - (Wk.Offset(0, 6).Value * BM.Offset(0, 5))
                              End If
                           Next
                        End With
                     End If
                  Next
               End With
            End If
         End If
      Next
   End With
End Sub

Your code is unclear. It would be more clear if you added the .Value property rather than relying on the default property to be used.

You set the data type for YU to be integer. Maybe you should have used Long or even Double if you have decimal values.

Thanks everyone. Your suggestions helped immensely.