The overall intention of assessing a compensation event is that the Contractor is no worse or better position and, in simple terms, should be based on the Defined Cost + Fee of Providing the works had the CE not occurred v the Defined Cost + Fee of Providing the works including the CE
Of the options outlined above, option a) may not take account of the Defined Cost + Fee unless both the Contractor and PM agree that the bill rates are representative of Defined Cost + Fee.
Both of options b) and c) are correct in that they establish the change in Defined Cost + Fee. I believe either options are an acceptable way of introducing the CE in to the BoQ but personally would introduce a new single item as outlined in option b).
Of the options outlined above, option a) may not take account of the Defined Cost + Fee unless both the Contractor and PM agree that the bill rates are representative of Defined Cost + Fee.
Both of options b) and c) are correct in that they establish the change in Defined Cost + Fee. I believe either options are an acceptable way of introducing the CE in to the BoQ but personally would introduce a new single item as outlined in option b).