It's difficult to fathom how much work has gone into providing QBO subscribers with every misguided, misunderstood, ill-conceived, off the mark tip option in our invoices. If any Intuit engineer/programmer has ever gone to a sit-down restaurant and/or bar I hope they would understand what we're asking for. 

This is what I (and I suspect many others) are looking for at the bottom of invoices that WE send to our customers.  

      Subtotal
      Sales Tax
      Discount
      Invoice Total
      Tip/Gratuity     <<<<--------  (customer enters amount they wish to pay, NOT prefixed amount or %)
      Grand Total  (Invoice total + Tip/Gratuity)

Tips are entered by our customer. It is not a fixed dollar amount or % of the invoice total. It could be 15%, 150%, or even $0. In the end... customer's choice. Not sure how to simplify this explanation further.