What is this new extension changes? Was the extension automatically granted by the system when submission is not made on the deadline? I quoted this from the student portal:
Extensions
If you require an extension on an assessment, you do not need to apply for it.
For the remainder of the Spring semester/ blocks, you’re automatically eligible for the maximum extension allowed on your course (two weeks if studying at Coventry University / Coventry University London, and one week if you’re a CU student studying in blocks).