What does the Price for Work Done to Date mean under NEC4 Options A and B?

The definition in clause 11.2 ties payment to the pricing document, not to cost. Under Option A it is the total of the Prices for each group of completed activities and each completed activity not in a group. An activity is completed only when it has no Defects that would delay, or be covered by, the work that immediately follows. There is no payment for an activity that is partly done, however nearly. So the activity schedule is your cash flow. Large activities mean long gaps between payments, and an activity with a Defect in it is not paid until the Defect is corrected. Under Option B it is the quantity of work completed for each item in the Bill of Quantities, times the rate for that item. Add the completed proportion of the work covered by each lump sum item. Option B is remeasured, so you are paid for the quantity done, not the quantity billed. Plant and Materials delivered but not yet built in are not part of the Price for Work Done to Date under either option. The exception is where the activity schedule or the bill provides for them. That surprises Contractors used to other forms. Implemented compensation events change the Prices, through the activity schedule under Option A and the bill under Option B. An event that has not been implemented does not reach the payment. Four mistakes are common. Option A applications claim percentages of activities, or activities that still carry Defects. The activity schedule is never updated for compensation events. Option B applications are measured against bill quantities, not the site. And lump sum proportions are claimed with no basis. The NEC4 Engineering and Construction Subcontract uses the same definitions one tier down. Has your main contractor paid nil against an activity, or a quantity below your measure? Then check its assessment against the activity schedule or the bill before you accept the figure.