NEC3 ECC: Option A itemised Activity Schedule - can I raise an EW if I feel client is asking for contractor to complete more work than we assessed was required.

The contractor is working on an NEC Option A with an itemised BOQ for the works. One of the items is carriageway patching. The tender drawing show 500m2 of patching and we visited site at tender stage and measured and priced for the same. After works has started the client has marked 600m2 of patching. I raised an EW as drawings indicated 500m2. His reply was that it was not an EW/CE as contract stated that contractor was to satisfy themselves with the quantities. Surely this is wrong as every tenderer could have assessed the patching requirements differently and we had to use the WI and drawings as our guide.

Has anybody any experience of a similar scenario they could share.