i've finally turned over the score on robotron! somehow, i'd gotten the mistaken idea that this happens at 100M, but i've now learned by experience that it happens at 10M.
first time i did this, i was surprised by the score turning over to zero, and i wasn't recording an .INP file, so there was no way to document the momentous occasion.
after playing a few more levels, i decided to kill off my remaining lives, to see how many there were, and i counted 37!
a few days later, i managed both to record an inp file and to kill off my remaining lives (17) just before the score reset to zero, so i could record a high score of just under 10M.
screen shot of the high score (9,977,700) is attached, as well as zipped .INP file (for any die-hards who may want to watch the 2.5 hour game).