Changes, fluctuations and fiscal matters Use of changes and provisional sums Valuing changes and provisional sum expenditure Market and tax fluctuations in costs Fiscal matters

Design and build contracts as a class need to be lump sum contracts, unless some other such control system as a guaranteed maximum price is used, so that the contractor receives a fixed payment in return for producing the works which he designs. As stressed in earlier chapters, there is no question of any difference in payment to take up changes in the contract design or developments of it in detail, which are forced upon the contractor by impracticalities in his intentions or similar contingencies, any more than to deal with estimating inadequacies in the tender. Pre-contract design and estimating are two sides of the same coin and, to confound metaphors, the contractor must lie on the bed he has made, as must the employer when once he enters into the contract, even if he finds an error against him in the contract sum.