Estimates of the cost of the proposed erection, reconstruction, alteration,
rehabilitation, restoration, or demolition and estimates of any additional
cost(s) that would be incurred to satisfy the HARB's recommended
terms for a certificate of appropriateness. Such estimates shall be
obtained from bona fide contractors or vendors deemed qualified by
the HARB. The number of such estimates shall be as required by the
HARB, at its discretion.