I rented a mid-size SUV from National at KOA last week, using the FlyingBlue code to get an all-in rate of $370 for the week, with LDW, supplemental damage, unlimited miles, all taxes etc. included. On return, they charged my credit card and printed out an authorization slip/receipt for $370, but while I was waiting for the shuttle, I noticed that I'd simultaneously received an emailed "rental agreement receipt" showing "time & distance" at $357, plus $63 for LDW, $91 for supplemental liability, and a bunch of other charges adding up to $607 total, with $370 paid and $237 due. Huh? I immediately went back to the counter and talked to the manager, who had no idea what the email was about and assured me that they'd only authorized a charge of $370 and that I should disregard the email. Sure enough, I checked my CC statement today and it only showed a charge for $370, so there's no immediate problem, but I'm still curious as to what this email represents. Is this National's computer system spazzing out on the FlyingBlue code? Anything I should worry about going forward?

Any other thoughts?