Along with all the timer, macro, and dusk/dawn information, the data downloaded to the CM15A includes a start date and stop date for daylight savings time. You can see this information in the ahpeeprom_w.txt file. As I've said before, this file tells you a lot about how the interface works, and should really be seen as a resource in absence of help from X10 directly. I'd be happy to help people interpret what they see there.
The change to the daylight savings time dates should not require a firmware change (which would require new interfaces for everyone, since the firmware isn't upgradeable) since it was designed to allow flexibility in the dates anyway. We weren't anticipating a change in daylight savings in the US when it was designed, but were making it possible to account for different dates in Europe.
If the daylight savings dates hadn't changed, no one would have had to re-download to the CM15A. But there's no way to for the CM15A to know about the date changes without re-connecting to the PC -- that's just unavoidable. However, once the XP patch was applied and you downloaded the change to the interface it should have adjusted correctly. Several people confirmed that the date changed for them in AHP -- did the time change work for you?