My results were exactly the same as Murphy's. The CM15A definitely does adjust its own time for DST, but it's using the DST date rules as they were before 2007. It does it by itself, without being connected to a PC. I've seen it happen several times over several years. I don't know if the dates are actually "hard coded", or if they can be changed by a download from Windows. But, like Murphy, I did a download (after clearing the memory) before March 11, and then again after March 11 to fix the time (which was off by an hour). But it is currently still using the old changeover dates, and not the new (2007) ones. I definitely am - and have been - using the latest greatest update of Windows XP. My Windows XP changed its own time correctly on March 11, and not on April 1. Perhaps the intention was for the CM15A to get its DST changeover dates from Windows, but that code has a bug or two in it.
It would be great to hear a real answer from somebody at AHP.