Mention your residence status in reply and attach your foreign payslips and/or income tax receipt and NICOP scan. Foreign income of non-residents or residents that is taxed abroad can't be taxed again in Pakistan. Make sure you reply in time as there is penalty of up to 100,000 Rs. for not replying to audit notices.
You can still be fined 20,000 Rs. for late filing of return for 2017, but its up-to FBR to make this demand. I am resident here and have replied to these audit notices 7 months ago, still haven't heard back from them. I have heard that it can sometimes take years for FBR to even read your reply. My relative's 2014 audit was closed after four years.