Look at how the tips were calculated. They were based on a bill of $95.65, the price of the meal before the service fee.
This service fee allowed them to increase the price of the meal by 18% without increasing the calculated tip by 18%.
They are stiffing their employees.
Edit: A $100 check would have an expected, 15% tip of $15. A $118 check would have an expected 15% tip of $17.70. What they are doing lets them calculate a 15%, $15 tip on a $118 bill. They are “stealing” $2.70 worth of tips on every $100 worth of sales.