It seems unlikely that random chance would lead to a 70/30 ratio for "best fit" either, so that just seems to be moving the phenomenon that needs explanation to layouts around stairwells, which certainly weren't standardised in the medieval era.
The ratio of staircases in Norman castles was more like 20:1 which is a ratio even more in need of a non-chance explanation; the greater numbers of anticlockwise staircases came later, when coincidentally or otherwise individual towers were less important to the overall defensive scheme
The ratio of staircases in Norman castles was more like 20:1 which is a ratio even more in need of a non-chance explanation; the greater numbers of anticlockwise staircases came later, when coincidentally or otherwise individual towers were less important to the overall defensive scheme