Under NEC3 ECC Main Option A (April 2013), the Employer has asked for an acceleration quotation and expects additional costs, but also that the Contract Completion Date and relevant Sectional Completion Dates to now be earlier.
63.3 clearly defines delay to completion. However, the understanding is that neither the Contract Completion Date or Sectional Completion Dates change to earlier dates and can only move to be later in line with planned completion movement ?
you are right a CE can only extend the Date(s) however acceleration is an expressed provision, BY AGREEMENT, to shorten the duration and bring the date(s) forward.
This is acceleration under clause 36 of the contract. The PM can instruct a quotation for acceleration to achieve an earlier Completion Date or Sectional Completion Date. If the PM accepts that quote then the Completion Date or Sectional Completion is now that earlier date, and the point at which delay damages will be applicable under X7. So yes, these dates can move contractually to the left by accepting the quote. It should be emphasised that acceleration is not a compensation event but a stand alone process. The PM can not make their own assessment of the Contractors acceleration quote.
The Contractors “planned Completion” or “planned Sectional Completion” will then subsequently show where they are in terms of that revised contractual milestone i.e. ahead or behind.