Trans slipping or funny CR thing?

[Tinman]

I have noticed that if I accelerate briskly in 3rd or 4th with the TC locked, there is a definite change in engine pitch at a certain load. It sounds like the engine is speeding up (TC slipping) but I can't convince myself that's it looking at the tach and speed. I run the Smarty on #9, stock TM and default everything else. Plus I had the DTT built to hold 500hp, so I'd be a little suprised and disappionted if is was slipping. I was wondering if it could be the ECM dropping the 3rd injection event of something like that. Any thoughts?