tedcloak, welcome to the forum.
I'm going to try to avoid commenting on the dealership model and their profit centers.
If you took the car in for a 'checkup' then presumably they looked under it and performed at least a cursory inspection.
Looking at the 2012 Mitsubishi Motors i-MiEV Warranty and Maintenance Manual Regular Maintenance Schedule, the first mention of motor coolant and heater fluid change occurs at 240 months (= 20 years)!
I hadn't looked at this booklet in years, and found it interesting that the only change/replace items are brake fluid (every three years/ 45,000 miles) and cabin air filter (once a year or 15,000 miles). Not even a mention of gearbox oil change unless the car is exposed to severe conditions
The cabin air filter is something you can buy online and replace yourself in about 30 seconds, if you don't want to simply take it out and blast it with some compressed air before putting it back.
We used to have an i-MiEV owner who got us a deal on cabin air filters. I just looked up a cross-reference: can anyone confirm that the STP Cabin Air Filter CAF1792 is the correct one for our i-MiEV? I didn't even bother checking Mitsubishi as the last time I checked they were 'discounted' to around $40. For reference, the carbon-impregnated cabin air filter for my Tesla from a Tesla Service Center cost me $7.50 last time I bought one.
For myself, discussions on this forum have previously pointed to perhaps changing the gearbox oil and brake fluid ... I even bought the oil, but have yet to change anything in my two i-MiEVs. I did buy a brake fluid test strip kit but have yet to try it out...
In nine years, the only thing I've done to my i-MiEVs is replace tires, the 12v batteries once, and the windshield wiper on one of the cars (I took the right side windshield wipers off completely). My i-MiEVs live inside the garage so don't get much UV exposure. Oh, and I had a dome light bulb burn out many years ago. The only regular 'maintenance' item I do is checking the tire pressures at least once a month. I have yet to see any change in any fluid level in the car, and that includes the original 12v batteries (which I've replaced with AGMs).
Dang, these electric cars are sure a lot of work... Edit:
BTW, it's always fun to know where in the world someone is located, as we occasionally find other i-MiEV owners close to us. You might consider updating your profile, the procedure described here: http://myimiev.com/forum/viewtopic.php?f=13&t=3196