I have seen plenty of rifles with the bullets buried in the case shoot good, but would it shoot better seated out farther, I really can't say for sure. I do agree you would see a pressure loss with the bullet out farther. I feel a little extra case volume is nice to have even when not needed or used. I personally do not like to see a lot of extra bearing surface below the neck shoulder junction. I like .060" just to have some to chase lands if needed.
I feel you are definitely giving up some velocity with your bullet seated this deep in the case. This does depend on what powder is used too as to how much, but I do feel all would benefit from a properly positioned bullet in the case.
Never tried 50 BMG in an EDGE, I typically use H-1000 but am getting ready to test some RL33 soon. I see RL 33 with some great velocity in this chambering.