Help with wording please?

[mogs0]

I am filling in a FIS form to get me on their website. It's asking about offering discount for families when they send more than one child. I want to offer a £1 an hour discount for siblings but can't find the right words!

I want to make it clear that the discount is for the child that comes the least or will be with me the shortest length of time. Does that make sense?

A few questions:

1. Will you offer a discount for more than one sibling, i.e. what about if someone wants to send 3 children?

1. How will you calculate "the shortest length of time" as most people won't know for sure how long they will book with you?

1. What about if both attend for the same number of hours?

Subject to that, how about
"A discount of £1 per hour will be offered for one sibling (or: for any siblings) attending my setting regularly. The discount will be applied to the sibling who attends the shorter number of hours. (If both siblings attend for the same number of hours, the discount will be applied to one sibling."
Does that work?

1. I hadn't thought about more than 2 siblings but I will have a think about that now.

2. I was thinking of a situation where the eldest child was due to start school in 6 months but currently came during school hours only but the younger sibling could potentially be with me a lot longer - I'd want the discount given to the older child rather than the younger.

3. If they attend the same number of hours then number 2 would apply.

Thanks for your help - I've filled in the form and said something like "£1 per hour, per family when 2 siblings attend".

I'm over-thinking it, I know! It would all be made clear to parents at interview (where I would ramble on for 20 minutes saying something that most people could say in 10 words ).