Well, looking at your stats for 6max tables, I am pretty sure you are playing too tight. your vpip is roughly 20%, which is acceptable for a 10 handed game, but way too tight for a 6 handed game. your vpip should be more in the range of 25-33%. loosen up for the 6max game and I am guessing you will see an improvement in your bb/100. Also, remember that players are more deceptive in the 6max game, and are more inclined to bluff or call with not-so-great hands.