04 Ram 2500 7.2,P0016, P0652, P0193, P0341

My 04 Ram 2500 7.2 started showing cam/crank position codes last year, i
replaced both sensors and truck ran fine.. for about 8 months. Then a few
months ago codes P0016, P0193, P0652, P0341 are showing.. Truck stalls
during start-up and when slowing for a stop, also stumbles when acceleration,
and if climbing a steep hill. Currently at Cummins shop in Reno Nv. I'm getting
worried about their diagnoses. They told me they could diagnose the
problem(s) for aprox. $850.. few days later the service writer told me they would
have to drain coolant to r/r cam-crank sensors and asked me to authorize
additional $250! I know this doesn't need to be done because I replaced both
sensors myself last year. Called B.S. on that, and then was told I was right. (no
kidding) My red flags went up then, and now they tell me my 100k engine may
be shot! They said my truck will not run now.. I DROVE IT IN! what to do now??