Commutation of annuity limited by gratuity status; permissible commuted portion determined by age, health and mortality tables. Commutation of annuity under the Income tax Rules for Approved Superannuation Funds limits the commuted amount: if the employee receives gratuity, the commuted value is the commuted equivalent of one third of the annuity; otherwise it is the commuted equivalent of one half. The commuted value is to be determined with regard to the recipient's age, state of health, the rate of interest and officially recognised mortality tables.