Difference between “bin … gewesen” and “war” in written language

Question

What is the difference between "bin ... gewesen" and "war" in written language? Martin Rosenau's comment on the question tagged below alludes to rules governing the use of them in written language, though I haven't been able to find these rules yet.

"In official German language (literature or newspapers) there are rules when to use which of the two forms. However for most native speakers in 'everyday language' it depends on the region they come from if they prefer 'war' or 'ist gewesen'. There is no difference in the meaning."

What is the difference between 'ist gewesen' and 'war'

Answer 1

You cannot use Perfekt in storytelling. Past events are in Plusquamperfekt there. So using Perfekt in writing is at most an indicator this isn't storytelling.

Der Außenminister war auf einer Dienstreise.

This may be storytelling or it may be about real events.

Der Außenminister ist auf einer Dienstreise gewesen.

This is a report. Written as spoken as perceived.

However, even newspapers are fluctuant in the use of Perfekt for their non-storytelling. I pretty much guess it's related to article layout.

If you are interested how this mess had developed and may be cleared up, you could read this article. But it's really hard to comprehend.