Etiquette, custom, accepted practice, even expectation is you tip or calculate gratuity on the bottom line. That should extend to 10 dollar served lunch or $250,000 weekly private charter(cash is expected by the way handed to the captain). All that said you are really paying for service. If you politely order a $$$ even $$$$ bottle of wine with no consultation and no support or feedback from the wait staff, followed by unexplained delay of a road dust covered bottle, no corkscrew, or even the hint of the proper clean glasses elegantly place in the correct position. I might show my disappointment in a tip below even well below 20-25% of the total check. In my experience great bottles of wine come with exquisite almost impeccably non intrusive service. Starting with the joy in the way the bottle is ordered, produced, opened, and served to each guest who shows interest. Unless something is terribly wrong we expect to pay gratuities of 20-25 percent of the bottom line. Back to the original point. I hate the automatically added or hidden service premiums. I also understand different cultures and different experience levels of guests drive the need for the action taken by the business owners. More and more when we experience better service from one person we tip in cash directly to that server with cash we pack just for that purpose. We generally have one bank envelope with only 1's and 5's for gratuities. We hand that cash over in the way we would want a friend or family member rewarded if they had done the work to serve our group.