In my experience, tipping the MMS won’t get you much of anything with the providers. There is a certain level of plausible deniability an MMS has and it’s better they aren’t privy to the goodies provided behind closed doors. The less they know, the better off they are legally because if confronted, they won’t have to lie.
Where the benefit of tipping the MMS lies is with things that involve her and certain aspects of traffic control with appointments. If you like to be flirted with, free snacks or maybe your own session with MMS with goodies, that what consistent tipping of MMS gets you.