Full Frontal vs Half Monty results?

I’ve been riding my KIKR for about 20 months now. Roughly, every three months I take a fitness test. I alternate between the Full Frontal and the Half Monty. Every time I test the Full Frontal my 4DP numbers drop by 10-15%. When I ride the Half Monty, they tend to come back up and above my previous Full Frontal levels. Progress, maybe? I understand that Full Frontal is a more comprehensive exam, but does anyone else see those drastic swings?

Ramp tests tend to overestimate FTP in some people, particularly for people who are more anaerobicly gifted like attackers and sprinters. After you do the tests are the workouts too hard after half Monty? I subtract about 10 watts fro my FTP after I do HM.

My 4DP ride type is sprinter and I tend to get higher FTP results on HM, but not nearly that much. More like 2 or 3 percent

My rider type is classisifed as sprinter or attacker depending on how I do with NM and AC. They end to be my strongest performances on FF. The workouts are noticeably harder after an increase, of course. My fitness level, or lack thereof, didn’t change overnight. Sometimes I adjust the level of workout to 80-90% in order to compensate for the higher FTP. I want to try a KOS this winter so I think I will leave it where it is for now and use the FF results.

I am an attacker and my FTP on Half Monty is ~20-25 watts higher than on the FF test. My MAP is even ~15-20 watts higher on the HM test. I generally use the max 5 minute power during the HM test as my MAP as that aligns better with FF results than the prescribed MAP from the HM results. I also subtract about the same amount from my prescribed FTP from the HM. For instance, HM will prescribe 353W MAP but my max 5 minute power during the HM test (gotta scroll down the test results to find this) was 338W. I will then use 338W as my new MAP and subtract the same amount (353-338=15W) from the prescribed FTP of 278W and get an FTP of 263W. This FTP is still a little high for me but in the ballpark, I’ll adjust if needed based on feel from future workouts. For reference I did HM and FF in the same week and got 353W MAP and 278W FTP from HM but 335W MAP and 250W FTP from FF, relatively close to the adjusted 338W and 263W.

Thank you for the insight.