If your instructor can provide a reference that negates the Civil Aviation Regulations then please ask him to put it up here.
It is not unheard of for instructors and text books to be wrong or misguided which is why the correct references are necessary.
The GFPT seems to have as many myths surrounding it as the perennial "over square" engine argument and the one that says it's OK to sign part 3 of maintenance release when you haven't even looked at the aeroplane. "My instructor told me...." is not a defence for not knowing the information if the
hits the fan.
The references are readily available and a thorough instructor would always show you where they are rather than saying "This is how it is because that's what MY instructor told ME so don't ever question it".