down in this thread, I mentioned a few times:
regen occurs whenever the computer determines that there is more power available than is needed at that moment to move the vehicle. Very simple. That is why you get regen with your foot off the gas. When you brake, the computer senese this and, of course you need zero energy to move the car, so it goes to full regen.

When you don't see regen and thought you would, its probably because the engine was not producing excess power- low rpms, or a local incline that you can't sense otherwise. Other than getting source code documentation, not sure what technical data there would be, other than finding out what the setpoints are.

A scanner would be useful for this- shows you engine loading, instant fuel consumption, and throttle position- all of which could be used to determine empirically what the setpoints are. I plan to get a scanner to turn off the 7500 mi service light when it comes on- maybe I'll try to pull some data and figure this out.

As for 6 bars- any battery that is continually partially charged and discharged will rarely achieve nearly-full charge. Just like your cellphone, laptop, etc- they're only at full charge after you give them a long time to charge, right?

IMA assistand length of assist is proportional to the battery charge- more charge, more assist. That is mentioned in the manual.