I paid for the massage. Tips are generally for any service I have not yet 'paid' for. Thats just how it is.
If a massage is very good, I will give her something additional even without 'extra' service, but it would have to be a very good massage and I have had thousands....
If its just an average massage, that is what the 80.00 was for, you don't tip your dentist, doctor, mechanic, or the guy at jiffy lube, they are providing services too.
Have I tipped for just a massage, sure many times, but it is not my normal practice as so few therapists give a high quality massage....Most are just average.