Let's examine what happens when they are installed:
Installation one:

I believe this to be correct for a factory new installation which has an untwisted cowl or windshield.. It matches the TM 9-8012 and make sense.
When you adjust the window upwards it also moves rearward. This makes sense because the purpose of adjusting upwards is to increase the angle to the rear at the top and have the windshield sit further aft on the cowl.
When you adjust the windshield downward it also moves forward. This is correct since we want the top angle more vertical and the windshield to sit further foward on the cowl.
Installation two:

I believe this to be incorrect for a factory installation because it causes the windshield movement to contradict itself when adjusting but in so doing this can often help when the windshield or cowl is twisted. It works well when there is a conflict between the distance from the top of the windshield to the rear tailgate top which effects the fit of the top and when there are conflicts with the windshield to door angle.







