I have been in the electrical power construction industry for 30+ years.
I have an MSEE and grad cert. in power.
A PE for longer than I care to remember, lol.
Still working in the field. I only share this as background.
It was hard to read, confusing, one single line would have illustrated it.
0.7 Ohm ground bed? No, 50 ' x 100' substation mats rarely get below 1, usually close to 2 when measured at 500', it decreases at distance increases. R = p LA
p soil resistivity
L linear distance
A area, A increases ~ L^2
The transfer switch causing issues:
Its contact R can't be measured with a meter, too low. Must use a MultiAmp current source and put a few hundred amps thru it and measure V drop., <<0.1 V or <<0.4 mOhm, 5' of 12 AWG.
His meter socket R likely is higher, or a snap-in CB. Or the component plug in the receptacle.
Nonsense.
The fact that a contractor he had done business with said '&$@%# no!!'.
A contractor turning down work!?
For a regular customer?