I'll do 20% of $200 tops, above that I'll round it up to say $50 or $60, there is no way I'm giving 20% of a $750 meal. No service in the world deserves $150 for a measly 20 minutes work. The entire tipping culture in the US has gone beserk, I'd rather tip the bagger at my local supermarket than give it some waiter that expects to make big bucks off an expensive meal, I reward good service but I'm not in charity neither can I be expected to pay a days wages of every waiter that helps me.