Thinks, and this is only a guess.
Would the vertical cg have an affect on the aircraft on rotation (or even when they tipped it up to move it sideways into the hangar) such that the cg would move far enough aft of the mainwheels and make the rotation uncontrollable? The Bev afterall was a tall aircraft and it carried quite a load high up in that tailboom.
It also makes me think that finding the vertical cg of the large airdrop loads was partly for the benefit of the aircraft and not just to control the over rotation of the load on exit.
Talking of airdrop lets not forget that it was the Beverley that dropped the heaviest single load from a British aircraft, a Heavey Stressed Platform weighing something like 42 000 lb, which is more than a Herc can carry.