1' Depth Difference from N to S

Cade Hammers has found an interesting anomaly in the dimension strings. The depth of the windows in the facade on the north side of the building is 5'8. The same dimension on the south side is 4'8. I would have thought the south side may be deeper for solar issues but this is the opposite condition.

I can't imagine there's a need for a foot deeper mechanical chase on the north side but that's all I could come up with.
Any ideas on why this may be?