Simple - after the second or possibly third request for a revised quotation give them a new one straight away which is the same as the old one with a new date at the top. This will force them to make their own assessment, which they have to do in accordance with the contract (and if you don't agree you can take to .
Clause 63.1 states the boundary between using actual or forecast Defined Cost, which is when the Contractor gave the instruction, or for other events when the compensation event was notified. This boundary is NOT reset every time that a new revised quote is requested.
Not withstanding that it is your obligation to substantiate the original quote as much as possible so that they can see if they agree or not with your quotation.
Clause 63.1 states the boundary between using actual or forecast Defined Cost, which is when the Contractor gave the instruction, or for other events when the compensation event was notified. This boundary is NOT reset every time that a new revised quote is requested.
Not withstanding that it is your obligation to substantiate the original quote as much as possible so that they can see if they agree or not with your quotation.