Well, if my FTP is underestimated, the good news is this sweet spot thing is working for me. Today I did a 3 x 20' session to change things up, and I have to say that after the first two intervals, which I performed as 1' under/1' over (~92% to ~112%), I felt like I was just getting warmed up. I had had no intention of doing a 3rd one, but I decided to try 20' "steady". The AP for the last 20' was 103% FT, and the last 10' was at 106%. Anyway, the AP for the 60' not including the two, 5' recovery intervals was 102%, or ~7w higher than my FTP. I feel like I have my FTP estimated quite accurately, unless it's going up faster than I can keep track of. I don't want to test too often. I guess I like to incorporate the "tests" into my workouts. The mental fortitude that I gain from the 90' to 3 hr sessions seems to be paying off in my shorter efforts. I will try a 5' max effort maybe tomorrow. I think I can probably do at least 120% FTP even though I haven't been training at this intensity.