Originally Posted by
BusTrav8yrs
There is an additional "special" bucket for certs that is not visible and has to have availability to be able to use them. You are fortunate that you found an agent not smart enough to know that and override it for you.
Interesting. This is my first time using companion cert and will probably be my last as it wasn't worth it. In the end I saved maybe 50 bucks b/c without the cert I would have been smart enough to buy on 2 separate PNRs to get the 1 remaining cheap fare. It's not worth the hassle and on top of that it makes the flight ineligible for upgrades (I know I'm only FO but my UG success on this particular route is close to 100%).