There has been much discussion about the difference between prices charged by the holiday industry during school term time and those charged out of term time.
If I was a PR representative in that industry I would make it clear that the standard cost is that charged in the period when schools are closed.
There is a reduction when schools are open (off-peak) because demand is lower and there is a need to attract custom.
In simple terms, prices are reduced during term time, not increased when schools are closed.
Railway companies operate a very clear and popular pricing system with their off-peak travel offers, a reduction on the standard cost.