No. The claims around "planing" are not at all explained by a description for why losses might be minimized. "Planing" is a notion that requires frame flex to affect the output at the riders' legs, and any explanation for it will probably require a biomechanical element.

This said, I do think that there's some reality behind Heine's observations. While his study was somewhat crude, and it did not sample a wide variety of flex characteristics nor very many riders (making it extremely hard to generalize or draw any practicable conclusions from), it is suggestive that something interesting is happening.
And I've had experiences that mirror his with regards to frames pedaling badly. A couple years ago I borrowed a friends' circa-2013 Pinarello Paris for a while, and my legs just didn't get along with it: it felt stiff, but the stiffness was less "rocket ship" than "kicking a brick wall." It was like I couldn't keep my pedal stroke engaged correctly with the cranks at my desired rhythm, my performance and self-selected cadence suffered even though my cardio had no trouble keeping up.