Have you tried it in first gear, that should make the pedals turn the most, I think? Doing the test in different gears will at least give you more info to pass onto Rohloff in your enquiry. If you can keep a note of how much the rotation is in each gear and the amount of pedal rotation varies as you go up through the gears, then Rohloff may be able to diagnose where the problem lies, knowing as they do, which planatary gears etc are ingaged in each gear.