Hello
Are you sure this guy was reading the meter correctly? All furnaces are checked at Install for gas pressures and as a part of warranty.
High water column gas pressures that high are very noticeable without a meter nevermind with a meter.
Theres no way im walking out of a house knowing its that high and yes ive checked it previously and it was never high and no where near close to even 3.8-4.0.
What was he there to fix?
If it was a limit or pressure switch or more like a inducer motor he needs to fix gas pressure issue immediately.
Most every thing on that Furnace is temperature sensitive and he CANNOT just walk out knowing this.
Email me direct please if you need my gasfitter to come out and adjust it because that guy failed you and thees no other ways to say it.
Keithmfg@gmail.com