I assumed that was obvious or I'd have elaborated. Basically, of the situations in which they differ, they do so by the epistemic making a better decision, but the instrumental having some other benefit. Decisions can be delegated, including the decisions of many to just a few, so you can have only a few people need to take the instrumental hit of strict epistemic conduct, while still having everyone get most of the benefits of decisions based in good epistemic rationality. In return for their sacrifice, the epistemics get status.

This is not a "how things are" or "how everyone should do" thing, just one strategy a coordinated group of rationalists could use.