I've written a good 3 lengthy emails about this, breaking down the pricing. It didn't work.

Even after the emails the tickets were booked so my math was useless. Lots of excuses are coming in from overseas now stating whythe later August dates couldn't be picked -- baby mama drama that she wouldn't let golden boy take her kids out of the country (they never married, split up and have major problems). Not sure why the earlier days in August are okay to take her kids to the US.
I think I've lost this battle b/c my husband only wants to do Disney with his family. He and I went together once and he said "not again, until we have kids." Disney isn't his thing.
By the way, for the poster that asked what my husband thinks -- he is disappointed in his family and tried to encourage them to change the flights. No success. Some of the family is now off to Barcelona for 'holiday' and can't be bothered. Must be nice to take 4 vacations a year with all that honkin' paid time off in the UK.
So I am so sad to report I think I've lost this battle. It's either no trip or a shorter trip to Disney when the UK family is there. I'd rather do some Disney than none.....I think.
I'm going to try for that room discount at 15% off.