K.E.
I think your potential set up sounds great, you have to entertain it. If your current sitter cannot understand the situation and the benifits for you then oh well. you need to look out for what is in the best interest for your kids/family. We as parents always have to make the hard desicions, sucks I know. I work full time and have a sitter come to the house mon. thru Fri. I love it. I pay a flat rate 1 kid or 3 kids it averages out so when there is no school I pay the same. I can budget and she can budget knowing in advance what $$ is coming. I also giver her a week vacation of her choosing per year paid. This locks them in who else does that. The flat rate is for 5 days if I take a day off she gets paid. If she calls in no pay. I am not supporting a ton of call ins here. I told her If our checks are not affected then either will hers.
It works out great!!
Good luck, and yes give her a try, I love the arraingement.