Originally Posted by
The Mileage Millionaire
Except, this functionality is NOT working as of this morning. I just get an error message...

If this is intentional, I'm done with UA.
Even if it is working, there is no way to know how many R seat are available. If it's just 1 on a popular route, it could easily be gone in the time you finish buying your W seat but before you try to apply the GPU, and we wouldn't even know.