So, you recently completed your "free" service check at the dealer for $370.00
I think you answered it yourself. Gee Whiizzzo....so you're asking if $370.00 is a normal price to change out maybe 5quarts of oil at what......1.50/qt? Maybe $4.00/qt if its synthetic. Say the pope blessed the filter and now it's $50.00 instead of the normal $20.00 We're still far away from $370.00 Which dealer was this. They deserve accolades for yanking that much money out of you sooo easily!
Jiffy Lube. Grease Monkey. Sears. Quick Lube. They can all do it for less than $50.00. Seriously. Take out the plug, gravity takes over, the oil falls out. Unscrew the filter, put a new one on, and add oil. Bingo.