Firstly this isn't a 'short' hornbow and it isn't a Turkish design(Crimean Tartar?). Adam's testing was on authentic Turkish bows. Turkish bow were only drawn to around 28 inch and obviously this chap is used to drawing 30+ so Adam has made a bow for his drawlength.
The Turks didn't use whopping great heavy arrows as the English did. The elb is a great design but its limbs can only move so fast. Long bow, slow moving limbs = long drawlength and heavy arrows. Great for shooting at a slow moving body of men.
The Turkish bows will shoot the big heavy arrows as well as a longbow....however when you start dropping the gpp then the performance of the Turkish bows starts to show. Turkish war arrows weighed around 600 grains and the bows were likely give or take around 100# = 6gpp.
So if you take into account that they fought in a completely different way, used different bows and different arrows you start to realise that you can't compare apples and oranges!
I shoot my Turkish hornbow with arrows of around 5gpp - there is zero handshock and my arrows are doing around 230 - 240 fps. When I used to shoot elbs all the time I would use arrows of around 9 gpp and be getting 180fps.