Actually, on that page there is another link. As I stated in an earlier post, most restaurants use the method proscribed in the information on the other link and have a negotiated percent of sales required to be reported which is often over 8%. It's still based on sales, and in your $400 bottle of wine example even in the lower amount, the server would be required to pay tax on a $32 tip, minus the amount tipped out. Assuming a 25% tip out, which will be based on a 15% tip, the waiter is tipping out $15 and paying $8 taxes, walking with a whopping $2 of your $25 tip. If you're comfortable with that, do it, but I wouldn't return to that restaurant. It'll take a long time to get seated, your order will either be held before it's put in or put in as a super-rush to get you out ASAP, it'll likely come out in pieces and be wrong and you never know what's in the food. And if you're on a date or with friends or business associates, you're going to look cheap.

Years ago, I was in FL visiting my grandmother's siblings. My Great Uncle, who invented several common household items (one of which I used a few minutes ago!), was well off and always paid the restaurant bill. But he was a horrible tipper and we had to be there in time to get the early bird special. He tipped on the final bill, not the amount before the discount, and never including taxes. And he tipped 10%. Knowing this, after the meal, I cornered the waiter and gave him $50. The waiter reacted strangely, but I wrote it off as meaningless. A couple years later, I was with several of those relatives and told the story. My uncle laughed and said he could explain; He had also given the waiter $50 at the start of the meal. Another cousin laughed and said he had also done the same. And I just recently found out the Great Uncle's son had also done it. So the waiter looked at me oddly because he knew getting $200 extra tip was wrong, but wasn't sure if he should admit it.