Im having beers at bar ordered wings and tipped $2 everything the bartender brings me.

Beer = $6

tip for beer $2

wings = $20ish

Tip for wings from bartender = $2

Total tips = $4

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Same order from waitress/er = $26

Tip = $5.20

Now I know this is micro example but extrapolate this over several drinks with food and the difference swings the other way. The question remains tho, am I tipping correctly?