National - PIT-No more coupons?

For 2 weeks in a row I've tried to use the National $35 off code for a week rental and it hasn't been allowed. Anyone else having problems?

Coupons are capacity controlled - if they are close to selling out - the coupons cannot be applied.

That's what I thought but they had a butt load of cars there all weekend. Hope this isn't the start of a trend. Weekly rental went up from $116 for a Premium to $206 for a full size!