There aren't many multis in this area, so this one is a very easy one that shouldn't take you too long to work out. The published co-ordinates will take you to a reserve with a sign that is black and yellow. Behind the sign, near the support posts are a number of nails. The nails you need to work out the final coords are the column on the far right (when you are behind and facing the sign.)
The final co-ordinates are S 36 55.ABC, E 174 43.DEF
A= Number of nails + 0
B= Number of nails - 7
C= Number of nails + 2
D= Number of nails - 7
E= Number of nails + 1
F= Number of nails +2
CHECKSUM= A+B+C+D+E+F= 33
At the time placing, the cache contained: Logbook, 1 TB and some SWAG for the kids. BYOP
Enjoy! make sure it is FULLY covered after finding it.