If you read Audie Murphy's Congressional Medal of Honor Award narrative and compare it to the movie (To Hell and Back), the movie really underplays his heroism and what he actually did. Perhaps this was due in part to his own modesty as he obviously had some control over what was portrayed in the film.
THAT is one glaring exception. And I think you are right, it was because he was personally involved and tried to keep the story at a low simmer.
Very good movie.