How Do I Automate Seniority Allowance Calculations with Specific Conditions?

Hi, I need your help. I want to automate seniority allowance computation (with an if condition) as per the attached sheet, but I am not clear about the formula. The criteria are as follows: seniority is 2% per year of service with a ceiling of 52%.

For Local Staff:

- Seniority comprised between 1 and 25 years = 2% x Basic Salary x Service Year
- Seniority greater than or equal to 26 years: Basic Salary x 52%

For Expat Staff:

Seniority allowance is not required, i.e., 0.

Thanks in advance, your help is very much needed.

To be more precise and accurate, please refer to the attachment filled with the IF condition. The cells corresponding to expatriates display "FALSE," whereas they should display 0, as expatriates are not entitled to seniority allowance.

Many thanks

The attachment was omitted. Here it goes.

Thanks