I also don't allow changes to the part-time schedule (so happy I don't have to deal with this anymore!!). I had one family who was part-time. She would often give me her schedule for 3 months at a time. The problem was that she often changed things around and I was constantly adjusting her pay/changing days etc. She still stuck to the 3 day minimum but it as a complete pain in the butt. So I changed my contract. I no longer allowed changes to their schedule once I received payment for the 2 weeks. So if they paid me (I get paid in advance) for Mon, Tues, Wed one week but ended up sending their child Mon, Tues, Thurs then they were charged for Mon,Tues, Wed, AND Thurs. Funny how they only did it a few times until she realized I no longer made adjustments to her schedule and pay.

Also on a side note I didn't charge a higher rate for part-time either so had no issue charging for stats regardless if it was a day they were to attend or not. I don't get too many paid days off and feel that all families regardless of days they attend should be paying me for that day. I never have had anyone complain.