Replacing coils in a 2014 when changing spark plugs
 

My 2014 has 60,000 miles and am having the spark plugs replaced.

I got some advice from a mechanic on line that I should also replace the 3 rear coils as long as i am doing the spark plugs.

The dealer says he has never heard of that; in fact he doesn't remember ever replacing the coils on a CX9.

Well, I am confused. Any advice?