Tesla Motors Club

We have enjoyed our M3SR+ for about nine months and apart from installing a set of mudflats the car remains stock. ( First car I can say that about.) I generally charge at home on a level 2 system. A recurring issue is that when I set the limit to say 70% and charging commences it will automatically change to say 85%. I then have to go and reset the limit to the desired 70%. Am I missing something here? Also would to have three set points on the Slipstart control, at least one of which doesn't involve the front brake actuation.