However, as she explains, the restaurant (or rather the computer) then calculates what 3 percent of that gross number is for the tip-share. @Flabigailfartin explains that, in this instance, she owes the restaurant $60. (She also notes that sometimes the tip-share amount isn’t exactly 3 percent of the profit she brought in, as certain items like alcohol are not counted toward tip-share).
Source: https://www.distractify.com/p/woman-explains-restaurant-tipsharing