I just got a BenQPE7700. I am getting a 16:9 screen between 140"-150". The BenQ manual says I can place the projector between 14.5 and 19.5 feet for a 150 inch screen. It will be mounted on the ceiling. I would prefer 19.5 as that will put the projector almost above my head rather than in front of me. I looked at projectorcentral and it seems to say something different. Can someone give me an idea of where it is supposed to be?