You can pay even 20% as Bonus payment depending upon the profit of company (or more but terminology used is "ex-gratia" instead of bonus).
But 8.33% as statutory minimum bonus.
In Provident fund, contributions are deposited based on the wages/salary earned by
the employee. However, as per Income Tax Act, Bonus is part of salary in the hands of employee
and taxable also.
'As per the provision of the Income Tax Act, 1961, the amount of compensation due or received by an employee from his employer in connection with an employment shall be taxable as salary in the hands of the employee. Accordingly, the bonus receivable by you shall be taxable in your hands as salary income'
Contributions towards PF shall be made on the basis of the monthly wages/salaries of employees.
You can not increase employers' contribution towards PF just for a month.