Service tax payments in cash exceeding rs. 20000 in value

I recently came across a client, which is a private limited company which has paid lakhs of rupees as service tax in cash. Should such service tax  be charged as an expense to profit and loss account? Also if charged as an expense would it be dissallowable as an expenditure under Sec 40A(3) of the Income Tax Act since all payments have been made in cash and exceed Rs. 20000?