Vo2 workouts are easier than Threshold while still having a significantly higher PL. Two workouts I have this week- Both have almost the same FTP%. Threshold intervals are 3 min longer with 1 min less recovery. Odd.
Washington +4 (5.2): 5x7-minute intervals at 105% FTP with 3-minute recoveries
vs
Mount Alyeska: (6.3): 6x4-minute intervals at 105-109% FTP with 4-minute recoveries
PLs are not supposed to be comparable across different zones. So a VO2 5.0 and a threshold 5.0 don’t have any correlation to each other.
I’m pretty sure I’ve seen 106% as the VO2max threshold so it looks like they are classified right and then you cant really compare PL across the 2 different zones.
technically I think its called crazy sauce, and you drink it.
ETA the official info from the FAQ section:
Are Workout Levels comparable from one Zone to another?
No. Workout Levels are classified in two ways: (1) Zone (2) Workout Profile. An example of Zones would be Endurance, Tempo, Sweet Spot, Threshold, VO2 Max, Anaerobic, Sprint. Each Zone has various different Workout Profiles within it. Workout Profiles represent the interval structure of the workout.
For example, the VO2 Max Zone has On-Offs, Float Sets, Sustained Intervals, Traditional, Attacks, and more. Workout Levels within a specific Zone and Workout Profile can be directly compared, while Workout Levels within a specific Zone but different Workout Profiles can only be loosely compared. Workout Levels between workouts of different Zones cannot be compared. For example, a Threshold Level 4.0 and an Endurance 4.0 will not have the same RPE.
For comparison outside of WOL’s: look at Duration, TSS, IF and KJ to see a different perspective on potential “difficulty” between these (or any other workouts).
And Washington is a +4. Maybe they should rename it once it gets above a +2 to avoid this confusion every few days. 
I think your ftp is around 275.
Threshold is roughly a 10W range and fluctuates a bit. Couple that with pass/fail. Do the math. Have a 
