My earlier testing may merely have shown that, given high skill levels, it's better to use unarmed alone than unarmed + staff, because of the much faster recovery time.

The bit about armsmaster not working is very interesting! It implies (and I have just confirmed) that a staff grandmaster with notable skill in armsmaster will lose some attack bonus and damage if they suddenly learn unarmed combat. (This wouldn't happen without an editor, because only the monk can GM staff.) More relevantly, a monk with high staff and armsmaster skills, and very little unarmed skill, will suffer such a penalty once they train to grandmaster in staff. Staying at master level is better for such a character!

Thanks for the correction.

BV