Gah...

It says 77% of your training should be below ~ 2mmol
20% should be above ~ 4mmol
And maybe 3% between

IOW, SST is dead
Either you are rocking above ~85% max HR
Or you are cruising easily below ~75% max HR

Sounds a lot like the stay-out-of-no-mans-land days of early 90's Carmichael/USAC training

The KISS principle applies = go easy when easy, go hard when hard