1) I'm not sure that I'm following - columns A and B should match? But you only check column B?

2) I also made an ugly mistake! Instead of
If (Sheets(WS_NA).Cells(i, 1) = Sheets(WS_patches).Cells(j, 1)) And (Sheets(WS_NA).Cells(i, 2) = Sheets(WS_patches).Cells(j, 2)) Then
I had
If (Sheets(WS_NA).Cells(i, 1) = Sheets(WS_patches).Cells(j, 1)) And (Sheets(WS_patches).Cells(i, 2) = Sheets(WS_patches).Cells(j, 2)) Then