Thanks for the drop, but that doesn't really answer the question - and the 'airport elevation' does not change!
The only (drop) bit (Section 6 - 260 I cannot follow is
"and the evaluation of the final segment delivering the aircraft to the circling area. Also see Vol. 1, chapter 3, paragraph 3.2.1b." whatever that means - that is the only factor I can see that might produce different numbers - but does not at all other airports we know of.
Is there anyone around who produces charts who can have a crack at this puzzle?