During the period of the Contract, Consultant or PTT TANK may advise Contractor, in writing, of changes in the Scope of Work. Contractor shall comply with such changes only if Contractor deems that such changes will not affect the cost or time schedule of the Scope of Work. Any costs incurred by Contractor to perform changes in the Scope of Work received from PTT TANK shall be for Contractor's account, and Contractor waives any and all rights to claim from PTT TANK such costs or additional time to perform the Scope of Work as a result of compliance by Contractor with such changes. If Contractor believes that any change in the Scope of Work may involve a change in the Lump Sum Price or time to perform the Scope of Work, Contractor shall require that the change be given in writing by PTT TANK in accordance with Article 10.1.1 above and shall comply with the provisions set forth in Articles 10.1.2 and 10.1.3, above.