[MPaulHolmes]

I think it's more the flow of current shouldn't have a preferred path to any one component. When the mosfets are off, the positive current goes in from M- bar, has it's pick of any of the 10 diodes to go through, and goes back out through B+. There's no reason one diode would get more current than the next. But with M- and B+ on the same side, the shortest route back out of the controller would be through the closest diodes to the M- and B+ bar ends with the mounting holes on them, so those diodes could get more current, but in practice it seems not to matter much.

Now, for the mosfets, the current comes in from M-, and exits B-. With M- and B- on opposite ends, there's no preferred route for the positive current to go. eenie meenie miney mo. I choose mosfet # fo. haha. But if M- and B- are on the same side, the mosfets nearest to the end might get more current?