When a surface is flat to .001, that is the specification for its flatness. It's not "off". If you want to get it to .0001, you can do that but it will cost a lot of money. "Flatness" is just a question of money. Look at your friend's surface plates or better yet, look them up online in the Starrett catalog or MSC or Enco. You'll see that as they go from Grade A to B, they're certified at lower levels of flatness.

Flatness is spec'd to the performance requirements of the tool. I don't believe that going beyond .001 will result in a better shave. Your face varies a whole lot more than that!

I have a bunch of new digital micrometers in boxes if anybody wants to start measuring their stuff.