Service tax and vat

it is correct...

yes it is correct. the only thing you need to care about is that s.tax is charged on the service portion and vat is charged on items liable to vat.

both r charged on the full amount...

If both r charged on full amout then it will be wrong

it is incorrect to charge both s.tax and vat on full amount. but yes, there can be one more thing that you must check. it may be possible that vat & s.tax has been charged on full value but at a reduced rate (i.e. s.tax may not have been charged at rate below 12.36%), so that if you calculate s.tax on service portion it comes to same value and same would be in case of vat.