The grand old Duke of York,
He had ten thousand men.
He marched them up to the top of the hill
And he marched them down again.
And when they're up, they're up;
And when they're down, they're down.
But when they're only halfway up,
They're neither up nor down!
The thing is, the mousewheel does not have an up or a down state, it is always in the middle. Why? well, because no matter how far up you scroll it, you can continue to scroll it upwards (Sisyphus). The mouse generates the signal once for each scroll 'tick'.
Unlike keys on the keyboard, which trigger a signal both when pressed and when released, the mousewheel has no 'release' signal. As for getting something like the wheel's absolute orientation.... I don't think that feature is available in mice at all...