sign(WheelDelta) tells the direction.Thanks @bytebits - very useful.
You can't see the benefit ?Thanks @jamie but I'm obviously being a numbskull :-[ - - -
With only one line of code, I reduce the + or - down to a -1 or 1 which can be used following without checking for the < 1 and > 0 etc.
You can use your MAG multiplier afterwards on that same value.
Also, you should test the size of the DeltaWheel because it can change, and your program will be left acting like a clown. There is an API for that too.
Do whatever makes your boat float as I say.