It never displays a 5th decimal although it actually tunes to that exact frequency. That value represents 10Hz steps and even 100Hz steps are unneccesary to handle or display in VHF/UHF frequency ranges.
An older scanner would probably both display and tune to 764.170MHz when you try to enter your frequency and that would be fine as it is only 1250Hz off and is within tolerance of commercial mobile radios.
