Is there an error on the time of sunset stipulated? What is the point of mentioning before or after Lady-day if the time doesn't change?

Time of Sunset.

As the period of sunset has been found constantly liable to dispute, it is therefore now regulated, that the sunset hours shall be after eight in the evening between Lady-day and Michaelmas, and after eight in the evening between Michaelmas and Lady-day,, and the back-carriage, after such hours, shall be taken to the carriagway pavement, or next standing beyond which the coach was hired from, (if hired at any stand off the said pavement,) at the full fare back to either, at the option of the party discharging.