I don't know if I understand you correctly but I don't see how this helps against a relay (not replay) attack. "anyway a rounding error compared to the price o

I don't know if I understand you correctly but I don't see how this helps against a relay (not replay) attack. "anyway a rounding error compared to the price of the car. But, more importantly," For car manufacturers rounding errors start many, many digits behind the decimal point. At their volume a cost down of a fractional cent is significant.