Calculation of sevice Tax

excluding vat

Yes. It should include VAT.

vat and service tax are two different things, however some venues cascade vat and service tax, please mention the service / commodity specifically to discuss the facts clearly. 

Service tax is tax on Services so materials and tax on that should be excluded but  In case of CAMC it includes VAT on products supplied with AMC (as it is contract of AMC inculsive of materials supplies of any deffect)......

yes agreed Mr sharma

while asking any querry the thread starter must be specific, bcoz there exist lots of provisos and exceptions in the law.