CP and FTP are conceptually the same. If you read Dr Coggan’s 7 deadly sins, critical power testing is one of them. Why? Because FTP is just a naming convention. A field testing method to estimate mlss.
There is no such thing as an FTP model. They are all critical power models with fitting parameters renamed. Even critical power is a naming scheme for curve fitting parameters.
And why would someone want to know their critical power? At least with one of the 15+ critical power models you can find online can be audited for assumptions, etc. AIFTP (CP in a trench coat) is a black box with no quick way to inspect why the values are the values being produced.
Same reason WKO5 model is weak from an auditing perspective. It’s derivative of existing models and appears to just combine a CP model with a logarithmic decay after TTE so it fits the data better.
Your study sample size has no real bearing on your CP model fit. Classic 2 parameter is two fitting parameters to MMP data. 3parameter adds Pmax.
WKO5 model has 4 parameters, FTP (CP), FRC (W’), Pmax, and TTE. golden Cheetas ExtendedCP model has 8 fitting parameters! But recent OmPD models have 4 parameters and many of the published models vary from 3-6 parameters.
That’s why I feel TR and WKO should publish their models for auditing. In the engineering world, all my software has Technical and Theory manuals to clearly explain the assumptions and equations. This is $20k/year software and they tell you exactly how things work.