I would try to locate someone who owns a commercial fleet of Vehicles and ask them if they use Oil addatives in their Diesels.
My guess is they will say no.
The exception might be the companies that are using 0.5 micron by-pass Oil Systems and are doing extended Oil change intervals.
They may put in an addative to replace depleted addatives or in some cases the addatives are built into the filter it self.

The commercial users of Diesels are the ones who know what will save them money and what would not. Meaning they also know what does not work.

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84 300D, 82 Volvo 244Gl Diesel