I spoke to one floor guy and he said that they estimate that the make your minimum bet off you per hour, so if you're playing blackjack at $25 per hand the make a total of $25 off you over a whole hour, of that $25 you can expect about 10-20% returned to you as comps....

I asked if i walk up and do a quick bet of whatever amount and he said that he would probably give a buffet comp, he had osme name for it too, along the lines of a flash in the pan thingie or something technical like that...