18. Contractors may try and recover the cost of preparing a change quotation. In general, this activity is being carried out as an obligation under the PFI contract. There are, however, some contracts under which the SPV can recover the cost of quotations within the cost of the Change. Commercial staff should ensure that the cost is only recovered directly through the change where this is in accordance with terms and conditions of the contract in question. Many sub-contractors recover the cost of producing quotations through their overhead rates (CAAS should be consulted where this is disputed by individual contractors) and, in these cases, additional payments should not be made. However, where the contractor has to obtain a quotation from a sub-contractor (including a sub-contractor from his own Group) in order to prepare his quotation, then he may have legitimate grounds for passing on to the MOD any charges levied by the sub-contractor, if it can be shown that no provision for these costs were made within the original PFI contract or in overhead charges. In general the MOD does not expect to pay for the cost of providing estimates for changes that do not come to fruition.