Good write up. I think it proves what most of us knew already. The LB are a very good cheap lead shell out to 40 yards, but for total comparison, they are not in the same category as these high density Hevi or Winchester XR shells. To me you are comparing apples to oranges and asking the LB to do too much. They are both great at 40 yards and in, maybe even 45 for the LB's.
I feel the problems with LB's are going to arise when bird distances are misjudged which will result in more wounded birds. What makes heavier than lead loads shine is their down range killing ability on misjudged distances. I have killed birds over 40 yards and seen broken legs, wings, necks, you name it. I just don't think the LB's will provide that kind of killing energy consistency.