Maintenance Service: I went to Titus Will Chevy(Olympia, WA) on 10/23/20 to have my 2017 Bolt serviced. (I purchased it in 2019; has 50K miles & I drive 6K miles a year) I brought a list of items to check. However, the first thing intake person asked was for me to have the following 3 things done: Coolant Flush ($150); Transmission Flush ($290); Brake Flush ($140). I realized from the manual, Coolant Flush and Brake Flush would be a 5 yr maintenance, at most. I said no. But what is a Transmission Flush? In searching the manual, no mention of "transmission" at all. If Chevy Bolts need it, how often? Any background on this would be helpful!