The readings on a moisture meter are just relative (at least as I understand it). What they need to do is measure a surface that is likely to be dry, then compare it to another surface. The meter doesn't read moisture directly, it measures density, which is affected by moisture. But other things can affect density, including core material, what type of glass/resin was used, how well the mat was wetted out, etc etc.
A meter is a good tool, but it's not a divining rod that will spot water a mile away.
Good luck on the Cig!