here is my 2 cents..
i shot my horton and can see very little difference from ground to top of my roof,about 15 ft high..

now, real life hunting from sproul..
all bucks i killed from 12 ft to 15 ft high,arrows would always hit high the CLOSER the buck was to you..
10/20 yds,now at 30 yds, it would come down..
so, out of say 25 bucks with a bow,20 or so was shot at 10/20 yds and i aimed real low on bucks side behind shoulder...
missed many because i aimed to high on side arrow went over back..

crossbow may shoot flatter, you guys are experts there on that....