Dear MB-
I know there is a dead horse in here some where........
but you;re just not "getting it"
++++++++Having laid a bit of tile myself and having worked in a tile store for a short period may have something to do with it. I will not accept shoddy work. Which is why I always warn anyone working on my house upfront. If you'll accept shoddy work that's your business.
But I agree with the consensus that .5 mm is nothing to complain about.