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.
The activity schedule is not Works Information (or Scope now under NEC4) so a different description or quantity in the wording of the activity schedule does not itself give rise to a compensation event.
In contrast to the two above, I would give a “may be” as the approximate quantities are mentioned in the Works Information and therefore a change in the Works Information is a compensation event. However, as they are given as ‘approximate’, whether it is or is not a compensation event would depend upon the amount of change from the ‘approximate’. What that amount is, is subjective though !