What is the purpose of spindle with longer non-drive side? I've just discovered that Shimano has 107mm and 110mm spindles in their BB (square taper) -- the first one is symmetric and the second one is asymmetric. I have read why BB spindles are right-asymmetric (longer) -- chainring clearance -- but Shimano released such BB that spindle is longer on the left side (i.e. non-drive). I don't get it -- all the trouble with clearance is on the drive side, so once you have given length, you make it double. Where is the need for longer left-side of the spindle?

It may have to do with the mating crank arms. Sometimes one side had more of an offset than the other side.