Thanks, everyone! I got my price down to $218 by using National's PR Code and the Entertainment Contract/Coupon ID. It was the same price using the PR Code, Ent. Coup. and Priceless Cont. ID.
I'll keep trying as our dates get closer. I only wish I hadn't booked our air fare through Travel Now. I was happy with the $165 fees last week, but this week saw some significant changes and it would cost $100 apiece to switch. I learned a lesson, but a rather costly one.....