How hard is Dry Peak supposed to be?

Tuesday last week i startd the Low Voume 6 week base polarized plan. As always, a plan starts with a ramp test, which i “failed” miserably. 4 weeks earlier i tested at 290 Watt FTP, and on the test i got 257 Watt FTP, but, i trust the plan and process so accepted the new FTP. The next day was the first hard workout which was Sheep Mountain.

Sheep Mountain is 4x 8 minutes at 100% FTP. So a threshold workout.
Which I started at 100% on the first interval, but based on HR, breating and RPE, it became very clear that 257 Watt FTP is not correct. So during the intervals i upped the intensity
1st interval 100% (target 100%)
2nd interval 103% (target 100%)
3rd interval 107% (target 100%)
4rd interval 107% (target 100%)
Based on this workout, looking at breathing, HR and RPE during the intervals, i concluded that 257 Watt FTP is too low, and set my FTP to 280 Watt.

Yesterday i did Dry Peak, which is 4x 8 minutes at 104% FTP.
With the FTP set at 280 Watt, 104%, based on RPE and breating felt like it was too easy.
So the second interval i upped the power, again on the third and the fourth interval.
1st interval 105% (target 104%)
2nd interval 106% (target 104%)
3rd interval 108% (target 104%)
4rd interval 112% (target 104%)
So again based on this workout, i think 280 Watt is still too low, the day before i actually did another hard workout, so my legs where not even fresh.

The next hard workout is Boundary Peak, which is 4x4 min at 106%, which is supposed to be a VO2max workout, which I already know, based on yesterday, with an FTP setting of 280 Watt is too easy. During these intervals, HR, RPE and breathing needs to be very hard.

Yes, doing another FTP test is the “best” thing to do, but I do not have the time to do that, sounds weird, but there is no place in my current schedule to do it, not so much of time, but because of being rested enough to perform it.

So how hard is 4x8 min @ 104% supposed to feel?

This is what I just dont understand about the TR approach to Pol plans???

They use 4, 8, 16m intervals all around the same intensities instead of recognising that each of those should be done at max sustainable power for the durations - which obviously will be very different!

4x4m IS supposed to be a vo2 session so should be whatever it takes to get there - 115-125% for most, while the 4x8m should feel like a max effort sustainable for all 4 intervals, with HR over 90% max for a lot of it but lower than you’d have for the 4x4 etc. 4x8 should leave you pretty much done by the end and not wishing you should have gone harder! Likewise 4x16m will be slightly lower intensity so you max out over the 4 reps.

It just doesn’t seem to make any sense at all frankly.