A thought on why...
Central engine/dash harness was much more conventional with no interruption at firewall, ignition switch interrupted other side of coil like modern cars, there was a single central fuse on most '32, etc.
Lighting harness, though, was just like 1931 with only real differences being dimensional.
Thought...'32 had firewall and instrument panel assembled to chassis so that everything electric except maybe the domelight was affixed to a driveable chassis needing only a seat to go for a ride. Complete body was dropped down onto the firewall at final assembly...does this suggest that the Model A terminal box was there just as an easy place to hook up engine wires to the rest of the system on the assembly line?