What great write up, thank you, not something most of us we would get to try.
I think it's all in the curve of the blade. By chance I was watching a you tube about butchering a bison in the field using flints, as part of a university project. The uni were paleo experts & the flint production experts, the Meateaters team were used to butchery. They all started with both-sides flaked flints on handles, which did the job but blunted easily. However, they were surprised to find the simple un-touched smaller single side flakes that were curved held their edge and cut everything better.
My pet theory is based on the vids of canadian indians using curved seashells and steel blades like shells - it's a longer curved stroking action as you rotate your wrist, ie. length of cut bid Swede identifies. Pressure flaked edges are inherently unstable as the production of them sets up stresses in the remainder.