Quote:
It seems that some approaches are optimised for QFE and some for QNH with nice round numbers for either one or the other.
Nice idea, but not the case. The approaches are designed using a set of criteria, with input coming from the local survey of obstacles, aerodrome lighting, missed approach paths amongst other things. The minima and platform heights are derived from this information and if they happen to be round numbers then it's serendipity.