A friend has an old campervan based on a Peugeot Boxer. He has recently had it chipped/remapped. He says the engine now runs at lower revs in each year for the same road speeds. I say this cannot alter as a result of increasing engine power - only by changing gear or final drive ratios.
Is it possible that the rev counter settings have been altered to give an incorrect reading? He says the guy spent a long time with the van plugged into a laptop.