If any applicant can clearly demonstrate to the approving authority that, because of the nature of the proposed operation or use, the parking and/or loading requirements of this section are unnecessary or excessive, the approving authority shall have the power to approve a site plan showing less paved parking or loading areas than is required by this section; provided, however, that a landscaped area of sufficient size to meet the deficiency shall be set aside and reserved for the purpose of meeting future off-street parking or loading requirements in the event that a change of use of the premises shall make such additional off-street facilities necessary.