The IMDB field in the user interface ("Movie Information" panel "Runtime" field) can be updated to the DURATION value manually and the information XML can be generated using the "Generate .nfo file with this data" Obviously, a manual method.
ThumbGen can be modified to automatically do the same, but I'm wary of changing long-standing, clearly understood functionality.
Obviously, the issue with the discrepancy is that the Jukebox/Favorite view will show the IMDB Runtime value (because Mede8er will automatically retrieve it from XML file) and once you press ENTER, the about.jpg will show the real video file Duration.