Half Monty results down, but not consistent with how training is going

Some numbers and history. 44 y/o male 67kg for 1m75 (how much that is in washing machines and football fields I don’t know :smiley: )

Just going to stick to FTP and MAP here

did a 4DP end of December 2021:
FTP: 220W
MAP: 273W
cTHR: 160bpm

did a Half Monty 14th of February 2022:
FTP: 244W
MAP: 310W
cTHR: 160bpm

spent the next months training and riding outdoors (XC MTB). Got injured in June. 2 months of no riding and started again in September.

Have been training with the following numbers set in SYSTM:
FTP: 244W
MAP: 315W (don’t know why it’s +5 compared to my test, but doesn’t matter).

This has been going quite well. I’m not saying it’s a walk in the park but I can finish the workouts without having to stop somewhere inside an interval. Examples: 14 Vise Grips, The Omnium, Attacker, The Rookie …

So I was thinking that it’s maybe time to test again. Had a 5 day holiday with zero cycling or other training. Did a 1h Z2 ride yesterday (so nothing tiring) and did the Half Monty again today.

FTP: 236W
MAP: 292W
cTHR: 153BPM

So all my numbers are down. The funny part is I lost a little bit of weight so the W/kg numbers are identical.
But anyway, this means that in 11 months time I have made zero progress wrt FTP and MAP, I actually even regressed, while I never stopped cycling except for July/August and my workouts with the older, higher, numbers actually go fine. If I would put these new numbers in they would become too easy I think.

When I look in detail in the graphs I can see that previously I hit the following numbers:
lowest wattage in ramp: 137W
highest wattage in ramp: 333W
HR at highest wattage: 171BPM

and in my latest test:
lowest wattage in ramp: 158W
highest wattage in ramp: 328W
HR at highest wattage: 165BPM

My absolute max HR is 174

To add some more context, I did a VO2MAX and lactate test a month ago:
VO2MAX: 57
first lactate threshold: 145BPM and 205W
second lactate threshold: 155BPM and 229W

TBH I always considered the 310/244 numbers of my first test a bit on the high side as compared to what I thought I could do on the road. The numbers I got now seem more realistic (especially FTP compared to the lactate thresholds), but I don’t understand how under the same circumstances these numbers went down compared to a year ago and especially since the higher numbers don’t give me any issues finishing my workouts in SYSTM.

Any advice?

Biggest thing I can see on the surface is the difference to max heart rate in the two tests. Personally I’d need more than just an hour of zone 2 after a 5 day break to be ready for a test. I’d considered repeating Half Monty at the end of your next recovery week.