I know what it is and had an early coach that every other day made me do a FTP test. It helped me in no way predicting pace. Learning how to ride a test is a start and knowing you can sustain power through the dark patches 8-12 minutes for me and make the end. Are you on a good day that day or not? I find it puts limits on yourself and on bad days has negative affects mentally.

I know roughly what power I can sustain in a half and full IM so I have a maximum number I try not to cross early especially in IM and the rest is what the legs are giving me on the day. Training is by feel based on how the legs are, long the efforts are and how many. Otherwise my coach uses the moderate, medium, mad approach. I’m a classic over trainer so I push those numbers and can adjust to how the legs are on the day.

Now the OP coach is going to lift his numbers and he’s worried and questioning why this happened. Maybe he was on fresh legs, maybe he has improved, maybe was the weather that day but now being worried about what that is going to do to your sessions and a coach that thinks they should be lifted from a one off is that really the way to train? Not for me...