i have had a little bit more of a play with the power meter. using the 'dank tombs' http://www.lexaloffle.com/bbs/?tid=28785 tech demo in pico-8 let me easily adjust the CPU load so i could get a better feel for the range of power usage, and it seems pretty consistant (crappy phone shot alert)

on full blast (140% cpu ?!?!?)

and wind down the torch to limit the cpu

i also did a little test (no free hands for photo) using normal 'battery' voltage, and actually the current draw is higher!! with the power sat @ 4v, my multimeter peaked at about 250mah which is the same as i got from my old project, so it figures really!! also my super accurate usb power gauge seems to be about 10% low, although that was @ 4v, so maybe it is not calibrated for that