NEC ECC: Who takes is taking the risk for a forecast compensation event?

We have notified our client of a compensation event.
We have been subsequently instructed to issue a quotation for the works.
We have provided a quotation for the forecast compensation event.
The event is likely to occur in the next few days.
The contract period for reply is 7 days.
We have been asked to produce logs for the event.
Our understanding is, given we have notified the client of the compensation event and been asked to provide a quotation for it, we are now taking on the risk on this element (we have priced accordingly). If we do better than forecast we should still be paid the forecast as this represents the risk we have taken, if we do worse then we will still be paid forecast.

However there is some suggestion from the client that should the actual cost be less than the forecast cost this will result in a reduction in the compensation event valuation. However should the event cost more than forecast it is anticipated the client will stick to our quotation. This is win-win for the client.

Are we correct in our interpretation of the contract? How, if at all, does the contract period for reply and acceptance or rejection of our quotation relate to this?

Yes you are correct in your assessment that this should be based on a forecast which is all mapped out in clause 63.1. It stops the “cake and eat it” scenario for the client as you describe which is not what the contract says.

They may however use the actual to say the forecast was not realistic in first place (you said it would take 10 days and it actually took 2 days) but they still should allow what would have been reasonable as a forecast for risk. This same clause emphasises that if the actual cost was more than a reasonable forecast and the quote is not yet agreed you can not revert to actual cost either.