In response to an inquiry, Lancaster Mayor Rick Gray informed NewsLanc that, although the ordinance (and the signs/meters) only say that Sunday is exempt at parking meters, it's the City's practice not to ticket on Saturdays.
According to Gray, this informal policy of not ticketing on Saturdays was started under Mayor Charlie Smithgall and is still followed.
Gray agreed that the ordinance and signs should be changed to reflect the practice.