Noticing a pattern emerge in my poker patterns

[Str8Fish]

I decided just now to look at how I'm doing at each of the sites on poker patterns at the 0.50/1 LHE level.

(Site) (# Hands) (BB/100) (Grade on BonusWhores)
Party 7500 3.14 B+
Empire 4000 -3.69 C
Stars 1500 0.42 C
Inter 9200 1.50 B-
Absolute 3000 -5.06 D+
Bet365 1000 -2.25 D

obviously I'm just starting off at some of these places, and the amount I lose at Interpoker and Bet365 is made up from the BonusWhoring I do. I don't think I'm goin back to Absolute until I'm at a higher level. I'm just amazed that table selection plays such an important role on my win-rate! This also means that me playing poker at the tighter tables is an awful thing for me. Does anyone think moving to 6-max might help in this area? Any advice for the tighter tables/sites in terms of what to read, etc?