Of course, when dealing with VBA it's different as well. False is still = 0, but True returns to -1. This should show it (in your Immediate Window):
[vba]?"True = " & clng(true) & ", False = " & clng(false)[/vba]

The bum part about Microsoft's SUMPRODUCT() (of course a reason for this forum) is that formula was never really meant to do what its main uses are for. Part of the beauty of keeping things open-ended, even if it is unintentional.