Little Bill,
I have just re-read your entire post. Nothing you are seeing is actually a surprise.
It is possible that you have gotten your head around the effects of voltage drop in the conductors. If one is dealing with this with no background experience, such confusion is to be expected. I have installed full battery monitors (both Bogart and Victon) on more than a few owner's boats in the process of an electrical upgrade.
If one is not aware of what a Progressive Dynamics 92XX can do, it will not make sense some times. The good thing is that I have only once actually disagreed, but that didn't really matter in the final analysis.
Let the PD do what it wants and watch the little flashing light and start to understand what it is about.
Matt