Do you have a picture by any chance how it was done?
I have the similar issue with my 2007 volvo vnl
the difference is i don' t have a problem next to the engine bay .
Underneath the cab and engine bay looking good but at the front drive axle
(3 square inch i guess) looks and it is thin after i knocked off all the rust
and i found a spot where the screwdriver goes through the rail if i hit it hard