As per the Notification No. S.O. 1414(E) dt. 11/06/2010, for employees who have retired on or after 24th May, 2010, the limit of exemption of gratuity has been increased to Rs. 10,00,000 from Rs. 3,50,000. Hence, the date on which the employee has retired from employment is important for determining the limit of exemption.
In the said case of yours, the employee has received around Rs. 3,00,000 gratuity in April, 2010, giving an impression that she has retired on or before April, 2010. Hence, the limit of exemption applicable will be Rs. 3,50,000.