Except annual return (e-Form20B) all other forms are required to file within 30 days to avoid the additional fee.
for further details kindly visit the following link "https://www.caclubindia.com/share_files/additional-fees-revised-w-e-f-5th-december-2010-32441.asp"
05 October 2011
Additional fee as per section 611(2) is also depends on the 'date of the event'. Fee can be automatically calculated from http://www.mca.gov.in/DCAPortalWeb/dca/MyMCALogin.do?method=setDefaultProperty&mode=15