OP, I think your focus is in the wrong place, like a few of the other responses have alluded to.
The importance of efficiency isn't really chasing a higher number, it is in CONSISTENCY. The commercial brewers don't figure out ways to increase efficiency, per se, they dial in a 75-85% efficiency on each of their setups then aim to consistency replicate whatever that number may be. This way they can rely on the fact that if they hit all of their numbers throughout the process, including the equipment's target efficiency, then they will consistently recreate the exact same beer.
So in the grand scheme, efficiency is really more important consistency in replicating past recipes. Once you get your system consistently above about a 70% efficiency, the aim should be replicating that efficiency, not UPPING it.