Okay, my DRW 1008IM (with V0156 firmware) seems to work with the DVDBitSet104.exe utility included with 55b3 and a DVD+RW. (Haven't tested it with a DVD+R yet.) The utility is definitely a different binary from the one included with the 55b2 firmware, which does not appear to work with the V0156 firmware.
The only thing "weird" is that the bitsetting utility recognizes the Media Type and On Disc Book Type both as DVD+RW, even after you set the On Disc Book Type to DVD-ROM. Also, DVDInfoPro continues to show the Book Type as DVD+RW.
However, in a different recorder (Plextor PX-708A, for example), DVDInfoPro shows what you would expect, with the Book Type as DVD-ROM, and the Media Type as DVD+RW.
At least it works now!