The problem with dash fixer is that it messes-up bits in the eeprom's memory and to a trained eye it obvious that something is amiss. Also the instruments workshop code stored will always be 00000 after corection. They use so called back-doors to hack into the eeprom and ussualy dammage the eeprom by locking it so unless you do use the same machine, you wont be able to adjust the mileage anymore.