Need help working out an algorithm... [SOLVED]

Alright, I'm working on an addition to a feature in my Mario game, hitting ? Blocks. My problem? I didn't actually do the initial events myself, and don't really know how they work. Some very helpful person here helped me do it a while back, and it works fine. Here's what that guy did:

<img src="http://oi55.tinypic.com/mszmvo.jpg">

That makes the ? Blocks bounce upwards when you hit them from the bottom, and then return to their original position. Now what I'm trying to do is the exact opposite -- if you use a ground pound from the top, they bounce downwards, and then go back up to the same spot. I got that to work on its own, but when I try to implement both at once, I can't get it to work at all -- hitting it from the top OR bottom does nothing.

So, uh... help please?

I've been needing an a to b to a movement for a while, but until we get one there's always a state machine.

http://dl.dropbox.com/u/666516/queenofb.cap

In this case the state is either over or under the block.

The cap should be a little easier to understand, if you get lerp.

Got it working, thanks. I don't really understand what lerp is doing, but I think I get the gist of it...