There's no difference between a .36 that's been joule creeped up to be 1.48j, and a .36 that's shot without any creep at 1.48j
You can produce the exact same results in an AEG anyway
My point is, even at the very low 1j range, a very heavy BB can still get better range than a lighter one. It's all about backspin.
The reason a marui M4 loses range when you put .30s in it is specifically because it's not putting enough backspin on the BB.