8-3/4" axle length / housing questions

my axles are big bolt pattern (BBP) with 10" diameter x 2-1/2" brake shoes, not the narrower 1-3/4" that I think is standard?

So the big bolt pattern axles are longer than the small bolt pattern? Or is it the BBP and larger brake backing plate that is causing the length change? If so, I wonder if the last guy had a set of Yukon's custom cut to 27-11/16" thinking that was the right for an A-body but didn't factor in the differences in brake gap for the BBP axles?

I sent an inquiry to Dr Diff ahead of ordering new axles, but he's apparently out of the shop for a couple weeks.