Difference in Missed Approach alititude for VOR/DME v RNAV(GNSS) approaches

[Gonzo]

Folks, any ideas? Am I missing anything?

Hamilton NZ, 18L VOR/DME approach has the missed approach climbing on runway track to BUDEN (12DME) at 3500ft.
http://www.aip.net.nz/pdf/NZHN_43.1_43.2.pdf

Hamilton NZ, 18L RNAV(GNSS) approach has the missed approach climbing on runway track to BUDEN (12DME) at 3600ft.
http://www.aip.net.nz/pdf/NZHN_45.1_45.2.pdf

Any reason why the difference would exist?

[FlightDetent]

Cold temperature envelope. Plus a cold temperature correction that I believe is misapplied. But I am no expert, though there's a recorded tendency to make more knowledgeable people rather angry.

[aterpster]

Gonzo:

Any reason why the difference would exist?

An educated guess: The holding pattern template that had to be selected for the RNAV missed approach was a bit larger than the template used for the VOR/DME missed approach holding. And, the larger template picked up a slightly higher obstacle than mandated a minimum holding altitude of 3,600 vice 3,500.

[Gonzo]

Thanks guys, interesting ideas that I'd not thought of.

[gear_down_two_greens]

I'm told by the procedure designers involved with the Hamilton charts that the RNAV holding pattern template is slightly larger than the VOR/DME template. The controlling obstacle is the same for both holds but the larger RNAV template means that they have to apply a 90m MOC vs 60m MOC for the conventional hold.

[aterpster]

green:

I'm told by the procedure designers involved with the Hamilton charts that the RNAV holding pattern template is slightly larger than the VOR/DME template. The controlling obstacle is the same for both holds but the larger RNAV template means that they have to apply a 90m MOC vs 60m MOC for the conventional hold.

I guess my guess was correct except it was the same obstacle that went from the secondary to the primary area or less in the secondary. .:8