My local dealer said that the Inverter and ICE coolant are separate services and the total charge to change both would be $210. Questions: I thought the coolant was one system and was for both the Inverter and ICE. Are there two different drain plugs? Is the dealer BSing me? Is $210 a fair price? I know there is no "flushing" involved. Just a drain and fill.
1. Two separate systems. 2. Yes. The cost for three gallons of Toyota SLLC is ~$75 and the total of $210 is very fair.
The two systems are independent. I cannot judge the price because I am in the UK. Draining is easy enough but refilling can be problematic to get air out of the systems, but you can DIY and save alot of your money. Just use the correct fluid "Toyota supper long life" coolant. It is not usual to change this until 110,000miles. If you have had the inverter coolant pump changed under the service campaign this will have been changed in the inverter system. If not get the pump changed under the campaign and it will be changed free of charge along with the pump. Leaving only the engine coolant to be changed.
Check with your dealer with the VIN number. Your post did not give the year of your vehicle, or mileage, this can be help full to us to give more accurate answers.
You would be much better changing the transmission oil if you have not already done so. This is a life time fill but most people on the forum agree it should be changed at about 50,000 miles as it gets very black (it is normally bright red) and has metal particles suspended in it as it is not filtered. It also looses it's viscosity.