PICD - Is the quotation issued in response to a PICD locked for changes?

A PICD for additional scope was issued to the Subcontractor and a response was received within the reply period. However, by the time the COntractor was ready to submit their response, the price of steel had increased substantially (£100/tonne). If the Contractor escalates the PICD to a CE, is the Subcontractor entitled to resubmit the quotation to recover the costs associated with the steel, or is the price locked as per the quotation first submitted in response to the PICD?

If the Contractor’s reply to the quotation was later than the date by which the instruction should have been given then the proposed instruciton is deemed to be rejected. In which case, if the Contractor instructs the work to be carried out then that instruction is a compensation event and an entirely new quote is submitted.