I believe there's a slight difference in the twist rates between the orange and green pairs which is why some manufacturers recommend one over the other as they tuned their devices based on the slight differences in cable length.

As an installer, we used A for years because many punch devices were labelled with A on top. After a few manufacturers recommended B we switched to B and still deal with the occasional "one end A, one end B" problem :-)

If you're dealing with loose wires like the phone guys it is a bit more important.