Cost per hand must be seen in relation to average pot size. Each hand is more costly in 6 max, but if average pot size is also bigger we cant make an argument for loosening up on the basis of cost/hand.

Many good players overdo their general adjustment to 6-max (too loose, too aggressive) and thus we gain lots of Equity advantage on them by playing tighter.

Only real difference is that we have no "early position" in 6-max.

My point is that the differences between FR and 6-max is far less important than the players at your table. Sometimes we get away with frenzy betting and other times we need to gain Equity advantage.

Loosening up just because its 6-max seems like poor reasoning.