If you say that you must do 12 stitches per inch then he will give up. I have seen few hand quilters that could achieve that. And.....as been said above it depends on how you count - what you see or top and back.
Strive for evenness first then work to smaller titches.
A good pracetice piece is 1/8 or 1/6th inch gingham check. Gives a good guide for even stitches.
Also appears to be mixing apples and oranges.....Is the post about hand or machine quilting.