NEC ECC: Option A - Activity Schedule: Can quantities mentioned in Works Information (and described as approximate) be subject to a Contractor claim for, in this case, additional works completed over and above those quantities?

The Works Info includes a length of trench for pipework, described as approximate in the Works Information. This guide chainage quantity is also split between two identical activities on the Activity Schedule.The Contractor is claiming the completed measurement is in excess of this quantity and is therefore claiming for the additional material cost.