Tds certificate validity

Syed Abbas Haider (article) (72 Points)

07 June 2017  
Lower Deduction Certificate u/s 197 has been given by the the contractor to our Company which is valid from 5 May 2017 to 31 March 2018. Whether we will deduct lower tds from May to March bills or we will deduct TDS on payments made in May to March period irrespective of the date of invoice. Please Clarify with relevant section. Thanks in Advance