See, I interpreted this differently.
It was agreed among these event producers to use score sheets that maximize tumbling scores at "half plus one" to create a majority.
I looked at it as saying that those EP's all agreed to define their majority as "half plus one". So, in order to get into the maximum range for tumbling scores, you need a majority...."half plus 1" creates that majority.
I went back and looked at the scoring grids for Varsity, Jam Brands, and Cheersport. They all had different requirements for getting into their max scoring ranges. Varsity just stated "majority" but didn't define majority. Jam Brands stated "majority" and defined it as half plus 1. Cheersport's ranges are divided out by thirds (which is completely different). Maybe all these EPs just decided that they would all agree on what they would require to get into that max range.
I could be way off base here, though. Just my interpretation of their verbiage. It would be pretty ridiculous if EVERY team was able to achieve a perfect score on tumbling difficulty at every comp. Seems silly! I really hope that's not the case.