I am sharing info I just gained and hope that it helps others
I have just discovered that:
1. Macros will trigger only when an address and command are received as adjacent transmissions. This means that a macro set to trigger by B12-ON will NOT trigger if the sender is sending a group command like B12, B11, BON because in that transmission, B11-ON is the adjacent address/command pair.
2. Some X10 devices such as the PR511 motion detector will send group commands if you set the available switches like +1 and +2.
I urge the X10 people to create a reference list of all devices that use group commands and to post same here and in documentation of the Activehome Pro so that users can troubleshoot for themselves. It was on this forum that I found out about macro triggers, NOT IN A MANUAL OR HELP FILE..it took a long time and required lots of effort.