I completely agree with you and our philosophies seem to be in sync. In the end we are doing the same thing. i just find it easier to add 5% to the total bill (especially after much food and drink). I should note that I previously mentioned I added $50 and this was because all 3x the bills have been quite similar. Much would depend on the number in one's party. What is more, over time the price will certainly change. When I first dined at TFL, the prix fixe was in the $150 range. It's now approaching $300. I make my decision on a case by case basis.