According to me, logically, a bonus is part of the CTC. As long as it is mentioned in the fixed cost, the employer is bound to pay it, even if it's a loss to the company (considering the Bonus Act). I discussed this with the labor commissioner in Mumbai, and according to him, as long as it has been paid to the employee regularly and recorded in the payment register duly signed by the employee, it should not have any issues.
Regards,
Nilesh C B