Agree that the percentage is quite high, but the net cost may not be that great, due to dynamic pricing. I looked at changing a reservation for a couple of weeks from now, and the net after discount price was noticeably higher. Yes it was 40% off, but the gross (regular) price was boosted up higher than I've ever seen it.

Maybe it was a capacity issue for the week I had booked the trip, but caveat emptor.