Just my two cents here. It's possible that your injectors are good.
When a DPF have many failed regens, the extra fuel give by the injectors ends up going on the oil, therefore increasing the level on the dipstick. This happens a lot in my small country with diesel vehicles with DPF because the engine just doesn't run enough. Usually short 3 to 6 mile trips to and from work for most people.
Now, the failed seals on the turbo would cause oil to go on the intake. We all know what happens when an engine eats oil, all that smoke and such is not good for the DPF and will plug the DPF quite fast. Then you get a bunch of failed regens. Everytime a regen happens, the ECU will send info to deliver more fuel to increase the temperature at the DPF. Again, with failed regens, the unburnt fuel ends up in the crankcase.
Most on vehicles, but some engines will have a mark on the dipstick above the regular oil level, that indicates that the oil should be changed because it's too much diesel diluted in it and increased the level.