I was using Matt F. 80/20 full IM plan. To my surprise it wasn’t Polarized plan as to what would one expect by reading Seiler’s et. al work. Majority of hard workouts were in 91-100% FTP and only few targeting higher zones. These Z4 (102-110% FTP), Z5 (above 110% FTP) workouts were present only in general phase. Later in the plan you will see only Z3 hard workouts. (Zone 3 in his book being 91-100% FTP).
So Hard vs. Easy were set to match 80/20 but “sweetspot / FTP” sessions were counted as Hard and used frequently during the plan.