The word that usually causes the difficulty in the AIP entry that you correctly quote is "absolute". It is tempting to interpret it as "mandatory, not recommended" but I believe that someone (IO540?) has a note from the CAA confirming the intention as "absolute, not relative to the minimum DH/MDH".
I find the use of absolute values rather strange. If you feel you need a cushion to avoid obstacles by more than the PANS-OPS margins, add a cushion. But it really doesn't matter what height above the threshold that corresponds to.