Wow, great question, I had never really considered that until you asked. I think the value of trying to do something like this is for setting up training zones and developing pacing strategies. Even taking an MMP curve is really just a best guess as I am certain I have never gone all out for 90 minutes. So under the context of this being a guide, I find that it tracks to a point. After 3 years of using this, I have learned that when I reach about 95% of my peak fitness for the season, I struggle to hit the CP12 and CP6 numbers (I have no idea why, but I can still hit CP1). Prior to that cross-over point the numbers are achievable (I do a 3 X 5's @ CP6 during the season which is my reference). That being said, over the last 3 years as my ftp has increased, there has been a close tracking of the 30,12, and 6 numbers. I am primarily a TT racer so that should give you an idea of where most of my time is spent. I should also add that as I move from late base to build, the lower CP#'s are more challenging, but after a couple of weeks they get easier so it certainly does take some work. So short answer, some natural tracking, but some work is required as well. I am certain it would not work the other way for me.