Service Charges: A compulsory charge for service, for example, 15 percent of the bill, is not considered a tip under the FLSA. Sums distributed to employees from service charges are not tips, but may be used to satisfy the employer’s minimum wage and overtime pay obligations under the FLSA.
A place implementing a service charge cannot classify it as a tip, even if it’s 100% passed onto the employee… a mandatory charge is not a tip, even if the restaurant encourages you to treat it that way. Certain states and jurisdictions tax tips differently than regular wages, and service charges are wages, not tips.