In very simple terms talking practically yes, although this is an area that the contract could and should be be more definitive/prescriptive. I have written an article that you will find on my website that tries to explain in more words than we have here as to why that must be the case on the following link:
The article gives reasons why this must be the case - although you have to prove what progress and other changes have occurred prior to the compensation event being notified. The Contractor cant just make up a story that suits themselves at this point and if they tried then the Project Manager would simply assess the event themselves.