framerate and PO

I've read the thread about Nvidia drivers...but still something escapes me.
Is there any connection between frame rate and the infamous PO?
Using a fixed framerate engine one could think that the higher the framerate, the more processing power needed, the more likely PO goes over 100% causing the slowmotion effect.
If this was the case wouldn't it be better to stick to a "reasonable" framerate (e.g. 25) to avoid incurring in slowmotion?
If not...where I go wrong?

I stick it on about 25 and can hardly tell the difference from higher frame rates apart from the smaller PO

The graphic calibration seems a bit stupid. When I do the calibrate graphics it reports that I get av 53 frames, with everything set to high, but when I start the game with these settings I get a PO of 280.

What youve got to remember the PO util takes some processor power. You can see this because when you view it the game slows down a little bit of your PO is just over 100.