Southern Hemisphere Compass - Worth it?

Hello All. I'm new to the group and to SCUBA in general. Was certified
in Bora Bora earlier this year (ANMP-CEDIP 1*) and and just recently
picked up a PADI "Peak Performance Boyancy" Specialty rating. Will now
proceed to get PADI Advanced Open Water in early January, 2006.

I just purchased most of my major hardware (Suits, Regulator, Octo, BCD
etc.), all pretty much Oceanic products (no, I don't have stock in the
company). For the computer, I selected the Datamax Pro Plus 2 with
attached compass.

Which leads me to my question. Oceanic also makes (as an option) a
"Southern Hemisphere" version of the compass head for that computer.
Since I do intend to return to Bora Bora perhaps as often as once a year,
(I'm New York based), is it worth buying the Southern Hemisphere head?

I'm not sure it's worth the money for using it just once a year at most, and
it's not like it's easy to switch the two heads - it does require a little surgery.
I could of course, just use it stand alone, but it gets awkward to use it that
way when you're trying to hold onto the computer itself. So if the "northern
hemisphere" compass is totally useless down there, I might buy it for there
and for the GBR in Australia.

Worth the expense/trouble?

Thanks very much for your help.



____________________________________________
Regards,

Arnold