I guess this would be a good time to add that the truck is paid for and "bulletproofed". "Bulletproofing",by the way, only solves one issue - the egr. It does not remedy the turbo, ficm, hpop, or fuel injector harness, which is the current suspect.
This truck has been 10 years of fixing one thing, and having another go wrong. Seems like every time I think I have fixed everything that could wrong, something else pops up. So the idea of fixing it again doesn't sit well.
I have every confidence in my mechanic, also. It's an independent shop, not a dealership. He has told me all along that the 6.0L is a "disaster". It's all that he works on - I never see a duramax there, and rarely a cummins.