I tested for roughly an hour, it could just be me but I think I finally got something (last thing I bothered to test)
Using Up Air, then mashing up-B afterwards seems to make you go lower. I could just be seeing things...
EDIT____
1 more thing that seems to make you go lower:
Using up-B while falling (and since I'm using TJ Off, I use Uair and fall a tiny bit before the up-B)
I feel downwards momentum counteracts the upwards momentum up-B gives you.
I did a quick control for the downards momentum, marking a certain point of the stage with a small thing of duct tape.
When I got below that point, I would Jump then up-B, I would LIVE AND GRAB THE EDGE.
When I jumped off of the low platform of battlefield, and up-B'd as I hit that point, I WAS TO LOW AND DIED