To answer your last question first, the mpg number reflects how far you went based upon energy derived when in the CS mode, whether or not the ICE runs all the time. Remember that regeneration when in the CS mode is a recapture of energy expended while in CS mode, and therefore attributed to gas mileage. Render unto Caesar...
The above may explain why your mpg creeps up after switching back to Normal mode: you are still using energy derived from CS mode. Hold mode is a sub-variation of CS mode. Does your ICE run constantly while in Hold mode, or are there periods of time where the ICE is silent and you are running on battery directly? That would indicate that you've got energy from regeneration being used. Maybe you have more of that than was used up before switching back to Normal mode.
What bridge do you use to cross back to NY?
The above may explain why your mpg creeps up after switching back to Normal mode: you are still using energy derived from CS mode. Hold mode is a sub-variation of CS mode. Does your ICE run constantly while in Hold mode, or are there periods of time where the ICE is silent and you are running on battery directly? That would indicate that you've got energy from regeneration being used. Maybe you have more of that than was used up before switching back to Normal mode.
What bridge do you use to cross back to NY?
