The Employer has made mistakes on an Activity Schedule they have prepared and they have no Z Clause in the contract, does the trigger a CE?
Under option A, the contract assumes that the Contractor produces the activity schedule and any errors in that schedule i.e. they do not price something that was within the Works Information (or Scope under NEC4).
If the Employer has produced an “activity schedule”, this is normally just for tender comparison purposes. The Contractor should make sure they price fully the Works Information, and I would always as a Contractor produce a more detailed activity schedule to reference in contract data part 2 as the Contractors mechanism.
The Contractor can not just assume that any errors in an Employers activity schedule is their risk - as that is not what the contract says, and not a reason within clause 60.1 for the Contractor to be able to notify a compensation event.
Option B with the Employer producing the bill of quantities would be a different story as the Employer does take the risk in errors in the BofQ, but not for the activity schedule under option A.
I agree with Glenn’s response. I have encountered this problem far too often where the contractor does not understand the difference between activity schedule on Option A and BOQ under Option B.