Taxes pertianing to ra bills of construction contractors

Dear Sir,

           I am waorking in Navayuga Engineering Company Limited at NTPC Prpject Barh, Bihar.

NTPC Deducted Following Taxes from our Certified RA Bills,,,,,,

WCT - @ 4%

TDS - @ 2%

Building Cess - @ 1%

Above Deduction is Applicable from Each RA Bills But if You have Taken any Moblisation Advance then a certain percent of amount deducted as well as interest @ 13% Deducted from Our RA Bills.

now its depend on LOA (Letter of Award) that Service tax will be Deducted from RA Bills or Not....