Max average volume (never got louder yet, but may try this weekend) is 80-85 dB with 95-101 dB in peaks. Most of the time the meter stays around 12 or moves for a second to 1 pm during peaks. Never stays over 12 for more than two sec.Those numbers are somewhat higher than I was anticipating for relatively low level listening in apartment circumstances. I believe that movement of the meter signifies that the amp is switching from class A bias to class AB, which would occur less often or not at all with one of the higher powered XA amps.
So if you sense that the main need for improvement is the ability of the system to handle those peaks as cleanly as possible, going to one of the higher powered XA amps may help. On the other hand, if you want to try to improve sonics at times other than when those peaks occur (which I suspect is likely to be more beneficial), based on the comments by JL35 and others I would consider upgrading to the XP-20.
Regards,
-- Al