What should I say to my student's parents?

This is a role reversal situation. Instead of me increasing the lesson fee, my student's folks wants to increase the fee by 30% as I've been increasing the tutoring lesson times by around an extra 30%. For me, I don't mind as I have the time, they treat me well and never skip a single lesson. If they want to pay me extra, I feel bad! Do you think it's a bit...er...pitiful if I keep negotiating the price down? Ha