The fact that you are questioning things is a good sign. Unfortunately, you will come across instructors from ab initio to heavy jet in your career who feel that being an instructor gives one the right to to add their own interpretations to already established practices and procedures. In many cases these may be good, but can only be taken as a recommendations not as legal and mandated. Where these recommendations are in direct conflict with your understanding, then you should ask them to guide you to the exact reference in the manuals that support their recommendation. With regard to the 3 points raised, the instructor is incorrect on all 3 counts and would have difficulty providing any written evidence to support his teachings.