If a higher level overhangs a lower zone, does BERS work out the shading overhang?
No. If the overhangs are less than 1200 you should ignore these because the engine assumes infinitely long eaves. We know in fact that the end effects can be significant so assuming infinitely long eaves can lead to significant errors. If the eaves on upper stories are wide and the eaves are relatively long with respect to the height of the building you can enter the upper floor eaves width in the 2nd eaves field and enter an appropriate vertical offset.
