My company allows me to use our Hertz code for personal rentals, and I've been doing it more often since prices have been rising steadily.

When I try to add a coupon code, be it for an upgrade, weekly or weekend $$ off, the rate changes back to the regular rate. That said, my corp rate is substantially lower than almost any other rate out there, so I'm not complaining.

Is this normal? I imagine it could be our agreement.