I feel your pain with this issue! We are at the 5 year maintenance point (though not quite at 150,000 miles) with our 2017 Bolt EV, and we've shopped between dealers' service departments for what seems like crazy costs for this routine maintenance work. And we've been given the run-around with price quotes - $275, $345, $550. C'mon now, which is it!!! We're scheduled for a THREE reservoir flush and fill this Friday 7/22/2022 at a Chevy dealership in Wilmington, DE while en route to start our vacation. After some hems and haws, we finally got a price quote of $345. Getting the Service Department to commit to starting and completing our work in timely fashion so we can continue our travel is the most recent challenge. Ugh!