Dear Suresh,
Can you please state which section of the Payment of Bonus Act or Income Tax Act says that more than 20% of (gross) salary is taxable? I have seen such a provision under the Payment of Gratuity Act that any amount received by way of gratuity over and above Rs 20 lakhs is taxable for the individual. Bonus being a condition of service is an expenditure of an employer and is like any payment made by him. I doubt if the payment over 20% of bonus qualifying salary will be disallowed by the Income Tax Department. If it is to be disallowed, then the entire amount exceeding 20% of minimum wages or Rs 7000, whichever is higher, should be disallowed. This is because under the Payment of Bonus Act, the rate of bonus is arrived at based on allocable surplus, etc. I am afraid any organization will go through such processes when the actual practice is either to declare a percentage of earnings by way of salary as a bonus or arrive at a rate after negotiating with the trade unions.
For income tax purposes, again, the expense is allowed even if it is genuine, and if not genuine, it will be disallowed even if you call it by a different name, like ex gratia for bonus. Therefore, if the employer wishes to pay a bonus, pay it. He can call it a bonus or ex gratia, or whatever he thinks fits.