NEC3 ECC: Option B - Bill rates or compensation event?

I’m currently undertaking an Option B contract with a substantial amount of drawing changes. Do i have to use bill rates or can i issue each change as a compensation event?

Without wishing to sound too pedantic I think the wording of the question is slightly confused. If the revised drawings are a change to the Works Information then this would be assessed as a compensation event. This is assessed using Defined Cost, unless both Parties agree to use bill rates (on a case by case basis). If these drawing changes are not a change to the Works Information(they might for example be giving detail as to what is required rather than the original high level outline Works Information), then “small” change in quantities can be assessed using the bill rates under a re-measure. However, bigger changes in quantity (which is defined in clause 60.4 as a line item changing by more then 0.5% of the total of the Prices) will be assessed as a compensation event and hence Defined Cost rather than bill rates (unless again both Parties agree to use them).

Hope that helps.