With fingers crossed, it appears this issue is resolved. I was never able to detect any kind of intermittent power interruption between the car and the door. So I noted the part number on the little white sticker on the bottom of the DDM. Actually there were three numbers - the part number and two other numbers that must have been some sort of codes. Then I set off for the pick-n-pull yard in search of a match. The closest match I could find was in a 2003 S60 (I have a 2003 V70.) The part number and the second number were a match, but the third number was different. I don't know what the third represents. Heck, it could have been a date code or anything. I looked at several 2001 thru 2004 S60's and V70's. The ONLY matching P/N I could find was in the 2003 S60. I never did find a 2003 V70 in any of the three yards I visited. $2 to get into the yard and $15 for the DDM. Took it home, installed it, and bingo - everything worked properly and has been doing so for two days now.

So I guess the lesson here is, at least with a 2003, it's not absolutely imparative that a reprogramming process has to follow a DDM replacement in order to make it work. Like replacing a DIM, with the correct part number and a bit of luck, the components can be replaced via plug-n-play.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)