Thanks for that, handy bit of math though isn’t it 120 * 0.89 = 106% , as 106 is the beginning of FTP, just shows that dropping a few percent to get through them really isn’t going to do you any harm, dropping to 89% is acceptable (I’d say for the long intervals)
If FTP = 250
V02 according to TR = 250 + 20% = 300
250 + 6% = 265
250 + 20% = 300 * 0.89 = 267