Goliath, you have been a huge help, thank you thank you.
Time IPO: for anyone playing with this, open Goliath's posted blend file and take a look at the ipo's and watch it animate, it is quite illustrative. Then fiddle with it.
Here is my understanding -> each object can have a time IPO that is independent of what any other object does. In a simplified explanation the time IPO acts like it is itterative, meaning it is essentially applied last, after everything else is calculated based on what the position/ size/ rotation/ material/ scale/ whatever (lets call it configuration) would be for that object at the frame in question. So if the time IPO is at 1 (1 on the Y axis) for the first 20 frames (which is 1-20 on the x axis), then the object will hold the position it would have been in without the time IPO applied at frame#1 and stay at that configuration for the first 20 frames. If the time IPO changes, the configuration of the object at frame X (axis) is made to be what the configuration for that object would be at frame number Y (axis) if there had been no Time shifting applied at all.
So the time IPO really isn't a curve, it is a set of steps (a histogram) where at each successive frame (X axis number) the computer displays the object as it would normally have been displayed at frame #Y (axis number) Since there are no fractional frames, eg no such thing as frame 25.4, every X and Y value is an integer (no fractions just whole numbers). So to the computer, there is no motion or direction, only snapshots of where objects would be at any given frame.
Example:: if the time IPO skips from (Y=) 7 right up to 110 between frames (X=) 25 to 26 then at frame 25 the object is displayed as it normally would have been at frame number 7 and in frame 26 the object is displayed as it would normally be displayed at frame 110, completely skipping all the frames in between. If you want to make things look like they are running backwards then slope the line down. So continuing the eg. if the time IPO goes from (Y=) 110 to 109, to 108 at frames (X=) 27, 28, 29 then at frame 25 the object is displayed as it would normally be at frame #7, at frame #26 and 27 the object is displayed as it normally would be at frame 110, at frame #28 it is displayed as it normally would be at frame# 109, and at frame # 29, the object is displayed as it normally would be at frame #108.
Please let me know if anyone has any questions. I have not yet tested to see if this can be used with the physics sims, like fluid or softbody.