i think a lot depends on the IM office / officer even in CW i am suggested to keep it up to date and bankbook updated the day we go to get the new extension
CW i have been asked for that to be included in every years extension especially if one has children but never had an issue on it just submitted the doc from school
David Young i also been adviced many time by the IO to bring a school certificate for the tuition fees and it’s added to the file even for an extension based on marriage in CW
it does work once registered and other than the other comments made with respect to registering it does take long and longer than usual to get a result outcome ( count 5-7 D to get a reply ) so start it in time