Originally Posted by
mrploddy
Raised a dispute with AMEX and they consider them fully posted charges so it's Hilton's problem.
I don't understand this bit.
If an incorrect charge has been billed to your Amex, tell Amex to dispute it. Don't bother mentioning the stuff about pre-authorisations. You booked two rooms and you were charged three times, the hotel won't help, so Amex should dispute one of the charges.
In response to the thread title, I've never been overcharged at a Hilton when paying using an Amex.