Judge
It is purely a function of whether the approach is flown on QFE or QNH. DH for a QFE based approach and DA for a QNH based approach.
The debate between the relative merits of QFE vs QNH will rage forever I think. The fact is that QFE works well in the UK but not in many other countries. My personal take is that it is time for the UK military to make the transition to QNH. But what do I know.
BV