Whether you wear a certain scent in the cold or warm weather, or not, is a very personal choice. Many people have summer / winter scents (like me) and many do not.
I think the advice about the M7 was most likely based on the personal experience of the person who gave you the advice - as a word of caution. However, you're going to have determine whether it applies to you or not.
Just yesterday I was speaking to another Basenoter about Booster by Lacoste, a scent we both own and love. He said it wore particularly well in the cold weather where he lives - and I mentioned that I never wear it unless it's Summer. For a second, I questioned my reasons why I thought this. So, I marched over to my wardrobe and sniffed the cap and instantly I knew why I don't wear it in Winter. Because it just doesn't FEEL RIGHT to me.