At the moment, there is very little information about communication to the CM15A/CM15 Pro. The owners of X10 filed for bankruptcy last year and sold all X10 holdings to a new ownership group that is trying to revitalize the brand. One thing they are looking at is removing the licensing for ActiveHome Pro. The issue is that they don't currently have all of the code to compile things into a working distribution, so changing the licensing may be difficult. Either way, as I understand, the new owners are not likely as interested in using the software as a source of income like the old X10 owners did. I have even heard that they may open source the code at some point.
Why does this matter? Well, if the source code were opened, it might be possible to get better/correct communication with the CM15 as the manufacturer intended. This would potentially include writing to the controller's internal memory for timers and macros.
HG can use cron to generate timer events. This works fine, but I wonder if optionally offloading these to the controller would make sense? Assuming the clock were kept correct (requires remaining plugged in or batteries being installed), the timers could run autonomously from HG. Does this sound like an advantage or just complicate things?