I meant electronic Application for Permanent Residence (eAPR). You can update info there such a way that it does not make you ineligible for the Round of Invitation you were invited under. For example, you cannot remove a work experience and add education to claim equal points after ITA. In your case, updating weekly worked hours does not affect your original crs score at all, so you can update it without hesitation. I have changed my Primary NOC code after ITA.
Good Luck!