I think so to... and I think that I am a creature, with lots of skills.
My barding difficulty should be:
225 (141 *1.6)
= (1175 - 700) * .275
= 130 + 700
So, my barding difficulty should be ~83, though this is open to some interpretation... does it take into account modified stats, or base. Modded skills, or base. Granted though, that wouldn't matter much, since it is over 700 anyway. Either way, I believe that my bard difficulty is somewhere between 80 and 85.
I think that the end resulting difficulty for provo is the average of the two difficulties. So since I am provoing things with a diff of upper 80s onto something in the low 80s, and my skill is mid 80s, I *should* be right in the sweet spot.
In the mid 80s I am gaining skill at a rate of roughly .1 per 100 attempts or so - maybe a bit less. I seem to get ~.5 per broken instrument. The problem is that friggen delay. I can use a weaponskill once every 1.25s. Provo takes 8, so I'm getting a gain every 10+ minutes.