Can you provide guidance on the application of Cl63.13 in an ECC Option B contract. In general previously I have built up CEs prior to the works using forecast defined cost using SSCC. What impact does Cl63.13 have?
As I understand 63.13 it provides the mechanism to record the CE. You still use the forecast of Defined Cost but, having done that, 63.13 provides that the result is pushed back into, or recorded in, the BoQ. This is because the interim payment under of PWDD is by reference to quantity and rate in the BoQ.
If you have 100m of trench at £10/lm in the original BoQ and then a further 100m is instructed and you assess that to be £15/lm you would need to adjust the BoQ either to provide the new trenching as a new item (because it is sufficiently different from the original and that is what is driving the price change) or within the existing item by combing the original and new so 100 * 10 = £1000 plus 100 * £15 = £1500 so 200 = £2,500 so the new linear rate would be £12.50 for trenching.
That is at least a lawyers answer, a QS may have a more sophisticated/different apporach
Whilst Rob Horne’s second option gives the right answer for this one compensation event (CE), what happens if more trench is required under another CE? This time it may be much easier to dig the trench and hence cheaper; using RH’s second method one has to reconstruct the rate again this time from three components.
However, if a new rate is required for each CE it follows that the existing item in the Bill of Quantities does not cover the particular situation of the CE and it can be argued that a new bill item is required. This then allows the second main bullet in clause 63.13 to be used to create a new Bill item (new description, rate and quantity). New bill items can be described in terms of the CE they relate to, making things clearer, saving reworking, and, giving a straightforward audit trail.