6. Deductions from earnings paid in multiple series
If your employee is paid in two or more series of payments at regular intervals, then you should select the series with the shortest interval between payments and use the correct table of rates for that period:
In addition, deduct 20 per cent of the net earnings payable in every other series.
If the person is paid in two or more series and all the intervals are the same length, then select one of these, make deductions as described above, and in addition deduct 20 per cent of the net earnings payable in every other series.
An employee's net pay is £150 weekly and £600 monthly.
A deduction of £7 is made for the weekly pay and £120 for the monthly pay (20 per cent of £600).