Some of it depends on where and when you are flying from/to. Years past I was never able to use mine. I could always find 2 sale fares cheaper than the required base fare for the cert.
This year I was determined to use it to fly my daughter & husband over Labor Day weekend to our family reunion. I kept checking back for weeks on end and finally the flights I wanted popped up in the usable fare bucket about 4-5 weeks out.
I have had better luck using the Reserve card certs for F travel. But still, you have to just keep checking back, just like we all do for award travel.