Route/Boulder grades discrepancy according 8a and Ondra

Adam Ondra has answered a question in the forum related to his comments of his latest 9b FA, where he said it is an 8C+ boulder followed by an 8b route.

"I believe that 8C boulder means 9a+ route and 8C+ boulder means 9b route. In case of Kout Pikle 9a+, you climb an 8C boulder and then you still need climb sustaines short power endurance section of 8c. But if you are lead climber and you make it through an 8C boulder, you cannot be ultra pumped and 8c on its own is not too bad for a 9b lead climber. Interestingly, I think that if the 8c topout was 7a topout, the route would be still 9a+. Maybe soft 9a+, but still 9a+. With 8c topout, it is hard 9a+ or maybe 9a+/b. In my case, I was fighting like hell in the upper 8c part while sending, and I had fallen once in the upper section before (arriving there in the end of the day, very tired), but I do not think that many people will fall in the upper part (if anyone will ever bother trying this funky routes).

For pure boulderer with no endurance, 8c part could actually be the obvious crux, but sport climbing routes are given sport climbing grades... In case of Taurus, it is 8C+ boulder and the topout of 8b doesn't add or change any difficulty. It might be mentally unnerving (I slipped once there), but that's all. And 8C+ translates to 9b route in my opinion. I would like to conclude that adding extensions or lower starts does not necessarily change the grades, as the the grades are suprisingly wide. And I guess that it is quite difficult to understand for many climbers and ignoring this fact is often causing confusion in grading."

The grade discrepancy diagram from 2012 follows Ondra's opinion although possibly an 8A boulder of 2021 is possibly more 8b/+ at the same time as a 6C boulder is equally hard to do as a 7a+ route.