Places of registration which are in the main office building of the county government in the case of election commissioners and in the main offices of the city government in the case of city clerks shall be open during the same business hours as any such building is open generally for business. County election officers may provide that any place of registration except a voter registration agency and division of motor vehicles offices shall be open for registration on Saturdays or for additional hours on any day or days that registration of voters may be provided.