If the appraiser believes that any work he/she has been directed to perform is beyond the scope of the contract or individual work authorization and constitutes extra work, the appraiser shall notify TxDOT in writing. If TxDOT finds that such work does constitute extra work and the cost of such increase in work would cause the maximum amount payable under the contract to be exceeded, TxDOT shall advise the appraiser. A written supplemental authorization will be executed between the parties, so long as the cumulative total of all work authorizations combined does not exceed the contract cap. The appraiser shall not perform any proposed additional work or incur any additional costs prior to both parties executing a supplemental work authorization.