Thanks to Roger1818 I now have, after months of work, my PR511 and CM15A almost playing together.
First:
The knowledge that the PR511 issues group commands was essential. The macro started to trigger when I limited the PR511 to outputting only 1 address (+1 in my case). This assured reliable issuing of the pair sequence B11 BON. The macro at B11-ON then triggered. When I had the +1 and +2 switches set it would issue B12, B11, BON and as Roger1818 pointed out, a macro triggers only when address and command pairs are received so for the sequence B12, B11, BON the address/command pair is B11, BON not B12 BON required to trigger the macro.
Second:
I feel fairly certain that the "front end" of a CM15A is functionally less sensitive than an appliance module or a chime. Both worked in a socket when triggered by the PR511, but when the CM15A was placed in the same socket with the above improvement, it still did not trigger!!! I got it to trigger when I moved it to a socket that was just 15 feet away from my XPCR (which I will now move to a location to allow me to relocate the CM15A to where I need it.
Third:
Even with the macro now triggering at B12-ON ( so I know it's getting the signal because it's doing it's thing), I still get no record of the event in the activity log. The log is set to monitor house code B, and transcieved codes to auto (A and B). Tomorrow I will add a phantom A switch, called from the B12 Macro to see if there is some reason why the activity monitor is not logging this event. The log is important to me because I want to keep track of visitors who pass by the PR511 in the driveway, that way, when someone charges me for 3 hours labor when I am away, I have the log to prove or disprove the statement.
Thanks Roger. If my test tomorrow gets the log working, I will post again to pass along the info to those who use PR511's.