Interesting example, your picture shows 40H->32H with cross. This leads to the same situation as mine, but to a lesser degree. 360/40=9 degrees between hub holes (and thus offset between flanges), and 360/32=11.25 degrees between rim holes. So if we align one side the other get 11.25 - 9 = 2.25 degrees off. To get equal distribution of the error both sides should be 2.25/2 = 1.125 degrees off (the angle that is 2.5 degree in my 36->24 case).

Was the pictured build made with some special tricks regarding spoke lengths and tensioning? Or maybe 1.125 degrees off is small enough to be negligible?