Input on service tax is done only on payment basis but excise input can be taken without payments.Reason is that Excise duty is paid and then only goods are removed but service tax is not like that only when it is paid then only credit can be allowed.Hope I made your doubts cleared
Guest
wht happn whn there is partial payment of bill eg a bill of 500 on which service tax is 51 total bill 551 and i made payment of 250 only