Well, is Mears right or is she wrong?
You should learn from what she told you. One does not make nouns plural by adding an apostrophe and then an “s.” Just the “s” will do nicely.
I know my grammar - I was in a rush and just did it automatically. To me it was juvenile to post a correction to me in public. I don’t correct people here. I fail to see why she even bothered to mention it.