wct

I am getting work contracts form a Government Organisation in Mumbai.I am getting contracts with materials.I have got several work order from the organisation below Rs 5 Lakhs.Now the total order value of the contracts is more than Rs 5 lakhs (for example contract 1 values 2.5 lakhs,cntract#2 value 1 lakh,contract#3 value 2.5 lakhs ,then #4 is 3 lakhs).

Now the WCT to be deducted on what basis?