There are seperate valuation method given for works contract.
1. When there actual separate bifurcation of Goods and Service (unless it is artificial bifurcation based on certain percentage) you are required to VAT on goods and ST on Service
2. When you are unable to bifurcate goods and service then above said valuation comes into picture I.e 40%, 70%.
Based on your facts, it is confirmed that there separate bifurcation of goods and service and they are charging separately.
Is it correct???
But somewhere your question is not complete, who is giving bills to you..?? Are you giving sub contact??
Kindly explain full facts and your question. It will help us to give right answer