NEC 3 Option B - Use of BoQ to remeasure a bill item

I’m currently using Option B and the WI states that the contractor is to lay 200m of kerbs and carry out 85m trench works to a specific area. The client has asked for the kerbing to be extended by 5m and the trench work 6m. In my eyes there is no change to the works information albeit the quantity has increased and as such I would use the BoQ rate rather than SSCC. The contractor is refusing to allow me to increase the BoQ item and references cl. 63.13. It is my understanding that the bigger changes in quantities are addressed via clause 60.4 where there is the opportunity to readdress the rate based on the actual quantity that has been complete. I have also consider cl.11.2(28) which notes that the price for work done to date is the total of:

• the quantity of the work which the Contractor has completed for each item in the Bill of Quantities multiplied by the rate and
• a proportion of each lump sum which is the proportion of the work covered by the item which the Contractor has completed.

Im not sure where I stand and I find the optin B clauses to be poorly writen, but thats another question for another time. do you use the BoQ to remeasure that specific item or is it done under the SSCC ?

If the Works Information is being revised ie the drawings are being changed to show an additional length of kerbing and trenching then that is a compensation event under clause 60.1(1).

The default to assessing the CE is defined cost + fee, it is only by agreement between both the PM and Contractor to use bill rates.