Moisture Meter

As we prepare to have our new wood floors installed, I am warned by college friend- be sure to check the moisture with a Wagner's MoistureMeter. He apparently has had difficulty (shrinking) with wood floors he had installed in a home, as well as difficulty with  a Timbertech deck failing apparently in the same location.
After many dumb questions back to said friend, I finally read about the Wagner's Moisture Meters ($395), and a bit about wood (engineered) floors and moisture, both in the subflooring and in the new flooring, and how their moisture needs to be within X % of each other. The more I read, the more confused I became. Now husband is an engineer, and at least somewhat understood what was being discussed. And I suppose one ought to ask questions about the moisture content in the new wood and the subfloor, but how do you resolve the differences? It was somewhat comforting to read that engineered floors (several layers of less than beautiful- and recycled wood- forms the base with a layer of beautiful wood on top is much less prone to being affected by moisture. But also that the rooms should be kept between 60-80 degrees.
Mind you, we have had wood floors (parquet in Hong Kong and VR condo and solid wood floors in current house which are 50 years old and varethane coated- which have had none to minor problems,  including our cleaning them with "water".
So I shall be interested to see what happens over then next few months with these new floors (Mohawk engineered Scotchgarded click oak floors- which will be nailed down.