where abouts on the coast are you?
i took my au to shift and drift 2 years ago for a power flush. my mechanic serviced the auto at 170k's and said it looked like the original fluid in it and i could get him to change it again every 5000k's for 2 or 3 goes til the fluid was 'clean' or to get the power flush - i went the power flush.
from memory it was about $180 and took a few hours. the dude at shift and drift dropped me at home then serviced the auto and came and picked me up
the workshop is at 12/ 15 Arizona Rd, Charmhaven.
i would think (others may correct me) that it would be better to service the auto and keep it running 'fresh' rather than letting it go and have the fluid turn into sludge and possibly need the auto fixed or replaced..
-tim