I purchased a new set of new Naniwa hones that i will give their first lapping with a DMT 325 over the weekend. I understand that lapping is necessary to give seemingly flat stones a true flatness necessary to optimally sharpen blades. Obviously it would be supremely important that the lapping stone be truly flat. Are lappers such as the DMT 325 built with a higher degree of precision and tolerance so as to guarantee that they are truly flat from the factory?