Making sure we are speaking the same language - I still do the five minute cooldown, so my total time in the ramp test workout is about 25:30 or so. As far as when I bail on the “ramp” part, I make it a goal to get to 20:00 since that is sort of proof to myself that my ftp has gone up by at least 2%. Past that, I’m not killing myself to eek out another couple of watts. I’ve noticed that while the workouts have been complete-able, the fatigue I carry has been a bit much, so I’m taking a slower pace with the ftp increases.
If you are making it to 24 minutes or more on the ramp part, that is a huge ftp increase. I think the farthest I’ve made it on one was 21 minutes plus a couple seconds, and that was after my first block of structured workouts.