NEC3 ECC: Can an implemented quote for an Employer's risk compensation event be changed?

Once a quote has been implemented for an Employer’s Risk CE, can the cost be changed/increased at a later date? Or is the implemented quote deemed fixed? For example, Contractor quotes to provide new gas main and all associated works. A quote is submitted and implemented. Several weeks later, the Contractor receives extra charges from the gas supplier for disconnection fees which were not factored into the original CE. Can the contractor raise a new CE for the same employer’s risk item to seek to a claim the extra costs which are associated with the previous CE?

Once a compensation event is implemented that is full and final and can not be revisited. You can however have a compensation event on a compensation event - e.g. you may get unforeseen ground you didn’t know about or weather issues in excess of a 1 in 10 year event which would then be assessed as a new compensation event. However, risk that you missed on the first quotation can not be revisited as you should have allowed for it in the first quote.