Varying number of overnights. Worksheet A or B?

This should be a simple question, but I haven’t had any luck finding an answer. Due to the custody arrangement the judge ordered, one year I have my two daughters 123 overnights and then with the addition of spring break week (custody alternates each year) it jumps to 130 nights. Also, alternating holidays can add or subtract another overnight here or there. There will be a few years where I only have 122 overnights.
There is a considerable difference between worksheet A and B in our case, and my ex insist that unless I have more than 122 nights EVERY year, we have to stick with worksheet A. It would seem to me that when something like spring break alternates each year, you would average the two. Is there anything that states which worksheet is used when the number of overnights varies?

Thanks in advance.

My best advice would be to average the two worksheets.