What constitutes reasonable child care?

Divorce states "Ordered & Adjudged pursuant to the Memorandum/Order after trial, dated May 7, '12, Plaintiff (ex hub) shall pay 80% and Defendant (wife) shall pay 20% of the reasonable child care expenses incurred by Defendant while she is working, limited to such costs attributable to the child, (name), & it is further..(goes into college expenses for older child). I looked into several programs, from cheap to outrageously expensive. I am working full time. I only am asking for 4 weeks out of 52 weeks of child care in the summer. My parents watched child free for 2 years while I worked.I have to pick a camp around his vacation. He chose a camp that has 6,7,8 yr olds & ours is 12yrs. his camp is $2K less than the 1 I picked which has door2door pickup. His I have to go out of way past my present job to drop off & p/u. & he wants a letter from my employer that I am working. (not in order). Do I have the right to pick a camp that works around my work schedule? Im custodial.