Are you taking enough vitamin C to help with the scarring? Since you are not that low on zinc, I don't think that's the main reason for your scarring but of course I'm not a doctor (not that most doctors know this stuff anw, like you said). Loss of collagen and genetics can play a part in how your skin heals after acne. So basically if you give your body the tools to facilitate healing (like adequate zinc and vitamin C), you may notice an improvement esp. on fresh scars. I'm trying out red light treatments and high frequency to help with elasticity and collagen formation.
Btw, vitamin D deficiency can also play a role in skin texture. Have you been tested for that?