one thing to verify is that all of these numbers are indeed miles, and not some are miles and some are kilometers.
but, with a shady enough mechanic with the right software, rolling the odometer back can be done. and I think (someone feel free to correct me if I am wrong,) that the odometer readings are kept in the cars ECM/PCM. If this has been replaced with one out of a used car, and not updated properly, the dash could read the odometer of the donor car.