Poker Tracker Auto Rate conclusion

I used the 6 player auto rate feature for 6 player nl holdem on Poker Tracker. I used the formula found in a thread on this site. It seems that it's not too accurate. For example there is a player that I've played against for 1000 hands, he's got -50ptbb, sees 83% of flops, pf raise of 29%, went to showdown 63% and won 40% of showdowns. He's my favorite player to play against but rated as a "good player" Is this the norm?