It makes sense from an optimization/mathematical perspective. Once you put a constraint on a problem (in this case maintaining a 90 degree bat/body angle over a large portion of the swing) the solution is typically going to be suboptimal in terms of maximizing/minimizing (depending on what you are looking at) the desired outcome. Typically constraints are things which are required by nature (eg conservation of energy,mass,etc) to occur and not conditions which are imposed through an assumption of what should be happening.
The only thing I would say which might be contrary to the data presented, is that the adjustments which are being made in the data shown may be out of reach for some hitters (due to a lack of athletic ability) in which case perhaps asking for more EC for these hitters might be beneficial...maybe.
My only thought here is function wasn’t being taught correctly. Any kid can flex and extend. It’s where depth comes from. As well as plane.