In reply to Simultaneously changing size of multiple glyphs in Fontlab?:
I'd guess that your UPM was different between BitFonter and FontLab (possibly 2048 in Bitfonter and 1000 in FontLab). In Fontlab, Font Information/Metrics lets you change the UPM with or without re-scaling to fit. Two steps; First, set the UPM to its original value (2048) without re-sizing. (You CAN leave it that way, in which case an OTF would be non-standard but your glyphs will be exactly as you create them). Or go on to the second step, changing the UPM back to 1000 WITH re-sizing. You'll then have a standard UPM for OpenType, but your glyphs will have small (sometimes imperceptible and sometimes glaring) differences because of the different grid size.