Just my opinion but I would not bother replacing the OCVs for preventive maintenance; I would need to see a mechanical issue first. That's based on my understanding that a bad OCV in and of itself will not damage the engine (people more familiar than I with piston to valve clearance over the entire possible range of AVCS in these motors may wish to chime in here). Of course it may be a sign of impending doom depending on why it has failed. If it's the more serious banjo bolt/oil starvation related root cause, replacing the OCV itself as PM would not have staved off that failure. If a sticky/bad OCV is the root cause of the AVCS-associated CELs, you can pull it out and try cleaning it to free up the action, and if that doesn't work then the solenoid could just be bad and you can replace it then, and everything should be hunky dory.
Preventive maintenance that I would do to keep the OCVs and/or your turbo and the rest of the engine from failing prematurely would include running a quality oil filter with the right bypass spec, and removing the banjo bolt filters entirely because they were a stupid goddam idea in the first place.