VARIATIONS that may be required during the normal course of the WORK are to be processed expeditiously and efficiently by CONTRACTOR. CONTRACTOR shall respond promptly to the requests for estimates showing the effect on Section 3 – Schedule of Prices of a proposed VARIATION and a schedule showing the effect, if any, of completing the proposed VARIATION. The revised schedule shall show any effect on any of the key dates as a direct result of performing the proposed VARIATION. The estimating effort associated with a proposed VARIATION will not in itself be a valid reason for altering the CONTRACT prices and rates.