I have costumer who visit me twice a week for 1,5hours. (Sometimes just once when he its too busy.) And he never ever ever ask for discount. Now after a few months i want to give him discount. But after my decision. But if he asked i won't and maybe these "good vibes" between us will be gone.
I have another a few regular costumers which i am happy to see. But wouldn't give them discount but i let them stay a bit longer and chat. Anyway i am not time watcher.
I guess you going o eat in your fave restaurant more then once a week and don't ask for discount And ask her of €50 is way too much! Did you think about her expenses??