Chapter 2 – Two questions

Hi, new learner and have just watched the first few chapter 2 lectures so far. A couple of questions:

When calculating income tax payable, will payments on account or CIS deductions come into play because I have only seen PAYE referred to so far?

Secondly, would it be sufficient in an exam to merely refer to ANI being above £123700 and therefore PA eroded to nil? Or do we have to show the full calculation?

Thanks in advance