One of my corporate client is rendering port services. It is outsourcing stevedoring/ cargo handling activities to another company. it is also given mobilisation advance to vendor and it is adjustable on some % while making payment for Stevedoring services to the vendor. Whether Service tax is applicable on mobilisation advance? if Yes,who is liable to levy service tax on such advance?. and Whether service tax(10.30%) is to be calculated on mobilisation advance(100%) or such advance is inclusive of Service tax (110.30%) and back calcualtion recuired?