Not quite. A $100 meal would have a routine 15%, $15 tip. Increase the price 18%, and a $118 meal would have an expected 15%, $17.70 tip.
Look at the tip calculations on this receipt: they are based on the price of the meal before the service fee. If this restaurant sold a $118 meal, it’s expected 15% tip would be $15, not $17.70.
They are stealing $2.70 from staff on every $100 check.