to clarify:

see? You're essentially just juggling existing global keyframes, in back and forth "scrubbing" action.  It's really like a time stretcher, if you see what I mean.

The tool you just unleashed is going to be awesome, too. I can already see some cool stuff to use it for...does it work on cameras? Nevermind, I'll be looking at it soon so I'll find out soon enuf.