Up to 50% of the parking spaces required for a theater or other place of primarily evening entertainment, for a church or for multifamily dwelling units may be provided and used jointly by banks, offices, certain retail stores, repair shops, service establishments and similar uses which are not normally open, used or operated during evening hours (beyond normal business hours of 8 a.m. to 5 p.m.) if specifically approved by the Borough Council; provided, however, that written agreement assuring the retention for such purpose shall be properly drawn and executed by the parties concerned and approved, as to form and execution, by the Borough Solicitor and shall be filed and made part of the application for a building permit. Such approval may be rescinded by the Borough, and additional parking shall be obtained by the owners, in the event that the Borough determines that such joint use is resulting in a public nuisance or otherwise adversely affecting the public health, safety or welfare.