If those measures are the same as in the US, I'm told 3-5 is typical for original paint. It is hard to get back to such numbers except by factory paint, even if you strip to metal and start over. Over 5, and surely up in 11-13 is at least one extra paint job, perhaps several.
My 79 Spider on BaT last year was all original paint except the nose between the headlights. Was 3 to 4.5 everywhere, 5-6 in the repainted area. I'm not an expert by any means but this is what I was told to expect, and what I found.
Andrew