Troubleshooting Power Drop

Hello All,
Grid Code Australia B only has an upper limit of 253v. My supply is hovering around 254.5v during the middle of the day.
Can the other setting AS/NZS 4777.2:2015 (AC Neutral path not externally jointed) be used? it has a higher input limit. FYI I am not exporting to the grid with the MPII.