6/8 deck vs. 2 deck Blackjack

Unexplainably, I seem to have more success at 6 and 8 deck Blackjack than I do at the doubledeck game. I am not sure why this is the case. Perhaps the reason for this is that with 6/8 deck, you can see all the cards having been dealt and then make a more exact analysis and decision on what actions to take. Whereas with the 2 deck game the cards are turned down forcing you to make decisions without considering these cards. I am just not sure what the reason(s) are. Any input would be helpful.