yeah the 30k service is always expensive than the rest.
there will not be much problem if you get it serviced in front of you.
you buy all the things yourself and get it replaced in front of you.
once i gave my car and left and they damaged the lower portion of the fender ( maybe the jack fell off , don't know)
http://www.theautomotiveindia.com/forums/ownership-reviews/7967-hyundai-trio-santro-i10-verna.html check my thread and see i always got normal services done from outside.
use the hass for Clutch work , AC work ( i have good ac mechanic near my home so i always go there even with my verna), anything related to engine , oil seals etc. works that are more complex. other things like changing oil , oil filter , air filter , injector cleaning , throttle body cleaning , suspension work (again i have a reputable shop near my home )can be easily done.