16 September 2016
You can do the process review along with capturing of the attendance. The amount payable can be tracked through the appointment letter on sample basis. The deductions can be tracked through the leave register maintained.
18 September 2017
You can only check the factual evidences which is provided by the company. As the calculation and the assumption is done by an expert, you need to rely on him for the assumption and the calculation. Kindly refer to the auditing standard SA 620