Monthly Incentive in Salary: Is It Guaranteed or Can It Be Adjusted?

Hi, can anybody please tell me if a monthly incentive is added to the fixed salary in the appointment letter, does the company have to pay the monthly incentive in full every month, or can they deduct this by stating it is a variable component.

Regards,
Chandrasekar

As a concept, 'Incentive Amount' is variable, and the payment depends on the real performance against set factors. For example, for production of more than 100% target could fetch X amount, and a lesser performance could result in X-. If the incentive is a fixed amount, then it becomes a constant, predictive factor and would soon lose its appeal as an incentive for improving performance. Employees might start taking it for granted.