Amtrak Guest Rewards - Upgrade Coupon

Could someone please explain how these work? I read the fine print on the back of the coupon, and it seems that you can only buy a ticket using this coupon one hour before a train leaves. Is that right? Thanks for any help.

You can buy the ticket any time at all. You can only *upgrade* your ticket within 1 hour of departure.

Yup. Book your travel as normal, and then talk to (phone or in person) a rep to get the upgrade within the window.