Here is an example of why you shouldn't concern yourself w/ this stat too much.

Sunday: $ won = $560 winning session % 55.55 or 5 of 9
Saturday: $ won = -$220 winning session % 67% or 8 of 12

interesting thread...seems similar to BlackJack...i played BJ for 20 years and i'd say i lost more hands than i won in those 20 years....BUT, i had an overall 85% win rate, i.e., won 85% of my sessions, lost 5% and tied 10%...weird...explanation there was spreading, i won more big bets and lost more min. bets....the big bets more than made up for all the min. bets...
When you have the best of it, you're going to win more big pots in poker, which offset the
slightly more smaller pots.