I have no idea if this happened in a recent version or if I've somehow never noticed it before, but if I have a seamless texture and I'm trying to pack a single face of a square in 3DS it always pads the edges and causes a seam since it isn't taking up all of the 0-1 space.
If I turn off padding when packing it still pads the edges and I can't find a way to force 3DS to move the UVs to the maximum UV space.
I can do it manually, but obviously I'd rather not spend time moving individual points in the UV editor if it isn't necessary.