That is a loophole, you're not using the same language test result to apply for your AOR as you're using to obtain your ITA, which should be the case.
I'm not so sure where your certitude on the matter stems from.
While yes, it's true that over the course of your application's assessment, as long as your CRS points don't drop below the cut-off score your application gets approved, however that doesn't mean that you can switch in and switch out information at your discretion post-ITA before you submit your AOR.
There is a reason why your profile locks, so that you can't edit the core information with which you received your ITA, because that's the basis on which your application will be assessed upon.
I think you're underestimating the situation.