I am sure the glow tech doesn't require such depth... I wouldn't think so either but who knows
The first question I would have is, what is "grade" in Florida... every decent construction site in Florida is way above true grade. To me finished grade could be any height so not sure if the heights now are what the end results will be
I find it hard to believe they are laying walkways so early as those are usually the very last thing installed. He might be confused then on what it is they are building
Is your friend in the construction business? Sort of