I have a 10A 13.8V Laboratory Bench Supply powering the mount. It is located at the base of the pier and uses the same power cable that came with the mount.
I had a productive video call with Mike and Dave this morning and we were able to resolve all of the issues. Most importantly, Mike was able to make a couple of CP4 tweaks which greatly improved the stopping performance of the mount with this heavy load. We also confirmed that slew ramping is indeed working but it is much faster than other mounts. It is also slew rate dependent so at 240X you cannot hear it, but at 600X it is definitely there. I asked Mike if he would bring up the subject of adding a user configurable ramping time for the mount given its heavy payload, or at least be able to have AP tweak it. Maybe specifying the load on the mount would automatically calculate the best ramp speed.
A big thank you to Mike and Dave for their excellent support. At this point it appears everything is working okay now.