Spark EV Tire Rotation...Not!

I have two 2015 Spark EV's and I love them - also have a 2016 Volt. For months I've been receiving numerous email and U.S.Mail from the dealers I got the Spark EV's from reminding me that at 7,500 miles I need to have the tires rotated. At that mileage I made an appointment for the one that reached 7500 first. Took it to the dealership and the Service Advisor came out and said the front and rear tires on the Spark EV are different sizes so they can't be rotated. I think the Owners Manual even says to get a tire rotation every 7500 miles. Something is wrong here - can the right and left tires (front and back) be moved to the other side? Is that the tire rotation that I should have had or are the dealers and Owners Manual just plain wrong? Or was the SA just plain wrong?

Front: 185/55R15 82T
Back: 195/55R15 85T