I would say that it all matters, WRTpacing what is the “damage” involved in someone with a 300ftp going at .75 vs .70? It’s only 15 watts....which isn’t a whole lot of calories over 5 hours....but it matters, sometimes a lot, not just with calories/inputs.

Does someone with the same FTP but short or non specifically trained for long course present themselves metabolically the same at .70 (IF) as the seasoned “battle hardened” LC athlete?

Combine with being on the wrong side of 50 calories an hour on the bike? Etc, etc.

The point being that going through the exercise of analyzing past performance in order to shed light or inform you on future performance is not exactly a new or novel concept in sport.

The (other) point being that you (we, anyone) can go through that exercise now, without a minute of extra training. And then armed with better knowledge on how to execute can hopefully make better decisions on future training investments.

ETA: if we look clearly at the numbers sub 2:30 HIM to 6+hours at IM (bike) is definitely not what I would classify as on the razors edge in terms of pacing.

In a general sense and at risk of sounding like a broken record, examine execution first otherwise it’s guessing, speculative, anecdotal, more art less science etc.

Maurice