I'd say your skill level assumptions are pretty close. I just started hitting balls this past few days after not touching a cue all summer. In our area halls, I'm considered an "A" player, and in the local bar leagues, I'm considered an "A+" player. So, I see this thread, and head downstairs to my mint condition 7' Valley Cougar bar table (just so you know what I'm playing on). I play 10 racks using BIH. I run racks 1,4,5,6,7,8,10. Racks 2,3...I lost concentration and missed after about the 7th ball. Rack 9...I missed on the last shot !!!! So, I run 7 outta 10 (shoulda been 8) and just started practicing again after a long lay-off. My point is...your pretty close on your figures.
Oh...and for the guys struggling...remember to use your opening BIH shot to break out the worst cluster. After that...its shoot easy...control the CB as much as you can...and try not to move too many other balls around. For you "B" and "C+" players...remember that you can control "follow" alot easier than you can control "draw". Stay focused.