No. You are wrong. It doesn't impact the score adversely in case the birthday occurs post recieving the ITA. This is clear as a crystal as per ministerial instructions. So yes, the scores are FROZEN as far as birthdays are the case.No - your score is never frozen. After AOR also - if your score drops then you need to inform CIC that my birthday has gone and etc. Please don't give false information. SCORE is never frozen.
(Anything other than birthdays however do result in lowering of your score.)