Call me slow, but I just figured out a little nuance of the Feedback system here.
I have 7 positive scores from trades and buys, but my score only shows 6.  Couldn't figure out why until I check out someone else's feedback info.
We only get scored on the number of trades with different inmates.  I had 2 scores from the same person, but the second one didn't count.  No big deal, but had me scratching my head for a little while.