This is fair, right?

[SevenwatersDaughter]

Good morning!

I've been looking after this one lady, we'll call her Amy, well I've been looking after her kid since he was two. Just on and off -- max six days a month. He is now four. My day care used to be open from 8-5. Now, it's 8-4:30. This is fine for all my parents but Amy. I told her I am willing to work with her on this and stay open until 5 for her. She said she appreciated it.

I'm thinking, though, that I should still charge her extra (my rate is $5 for every 15 minutes they stay past 4:30). So this would bring her daily bill from $40 to $50. Does this sound fair? It's what I would do if another parent phoned me up and said they needed me to look after their child until 5. I'm flexible, I CAN look after them till 5... but since my operating hours are 8-4:30, and in my parent's handbook it says that if kids stay past 4:30 it's $5/15 minutes extra, should I apply this to her too? Or because she is going to ALWAYS be picking up at 5 (or later -- 5:15 sometimes) should I waive it and make an exception for her?

What are your thoughts?