Mercury PM on Injectors

I recently got caught up with a lot of PM on my Mercury 250xs. I asked to get injectors cleaned, but mechanic said he could tell by the sound of my engine and the way it idled and ran that they were fine and it wasn't necessary. I have since had a couple of others tell me that wasn't possible. There was some other sketchy stuff from that shop on that PM. Now, I am wondering if I should take it to another shop and have them do the injectors. Is an injector ear test even possible by the best of ears?

I send a lot of injectors off to get clean and 90% of the time they could you a cleaning and motors seem to run better afterwards. We can pull the injector out anf get them cleaned also I get the air injectors cleaned .

No. Optimax technology runs on the lean side already. Injector cleaning and flow testing should be considered routine maintenance.