PTR on prescriptions & withholding tax

Hi! Newly licensed physician here and I’m still very confused about adulthings 😅

1. Do we need to indicate our PTR on all our prescriptions?

2. For moonlighting gigs, a tax lawyer told me that we should only be charged 5% for tax instead of the typical 10% deduction. Do you have any experience about bringing aling a sworn declaration to your moonlighting gigs so that only 5% is deducted?

Thank you so much 😭