I would have the tech remove the dry exhaust elbow and look in the turbo throat for corrosion. This is a known problem with this installation and is caused by a poorly designed exhaust system.
Just as important is to remove, disassemble, clean (both sides) reassemble with lots of water proof grease and new o-rings, pressure test and reinstall the after cooler. The after cooler can corrode the aluminum to bronze interface and cause the o-rings to leak sea water into the engine air intake. Do this every five years- not hour dependent.
Then maybe if there is any indication of over heating, rod any plugged tubes in the main heat exchanger, remove any zinc or impeller bits and acid flush the complete system.
This work can be expensive, probably $5,000+ combined with what you have already listed.
Not sure what you mean by changing the clutch oil and I wouldn't worry about adjusting injection pressure or adjust fuel injection valve. Not sure if the latter two are adjustable or what the fuel injection valve is but if it runs without making white smoke it is ok. Injection pumps last a long, long time and rarely need service.
Who said diesels are cheaper to maintain than gassers, although some of this stuff is sea water based and would also be required for a gasser.