There are a lot of ill informed furphies and just plain old wives tales out there. Just remember one person has to be in charge and that’s the FE. They can exercise authority at any time.
ps. You can’t log ICUS for an RPL because you don’t hold a pilot license until after the test when CASA sends it out to you.
If you’re told anything else, ask for a reference, such as I gave. No misinterpretations then.
