Assembling the Ackermann plate, is there a reason why the hex head is at the bottom and the nuts are at the top in the plate?

When assembling according to instructions the nuts turn in the Ackerman plate before they are tight and there is not much room to get needle nose in there (It can easily be done, it just seems wrong and theoretically would work fine with the hex heads on the top?).

I'm assuming there is a reason for this that may be discovered as I continue building.