Anyone knows how thick the clearcoat is on the A4 2005-2007?

I had a really bad scratch on my left rearfender that now is hardly polished.

After the polish i have 12my less paint than on the other side.

So the question is, can i polish the car anymore, or is it possible that i go thru the clearcoat.

What i read is the avarage clearcoat 30-40my, and is that true i dosent have to worry.