Salary Sacrifice Childcare Vouchers and NMW

Hello, I believed all salary sacrifice agreements would reduce earnings when completing NMW checks. However, I have recently started a new job where a NMW check is completed on the payrolls each month . In this check, the salary sacrifice childcare vouchers (the legacy agreement) is not considered and the notes for completing the check states that as these are legacy childcare vouchers, they do not need to be considered. However, as all salary sacrifice agreements reduce contractual pay, I would have assumed that these childcare vouchers do reduce salary for NMW purposes. Can you please confirm?

Hi Jackie. 
To answer your query we need further details about the arrangement, like number of hours worked and rates of pay. 
Please conract  ACAS on 0300 123 1100 and ask to be put through to the NMW team for further adcvice. 
Thank you.