The "My Compensation" page shows the employee, the current compensation. However, the Income Tax computation page shows the values and taxes based on Actual salary that has been paid along with projected salary.
The difference in values on both the pages can be because of two reasons:
Date of Joining: If the employee's has joined the organization after the start of the fiscal year- LOP: In case there are any LOPs in previous payroll, the Income tax computation would consider the actual value, however on the Annual Compensation page, full value would be shown.
For an Example: A. if an Employee join in the organization of 10th May then his/her calculation of salary based on total no. of Paydays 22 days it's called Earning salary (actual value) of particular month but in employee compensation his/her salary show Rate salary. Salary of employee in income tax computation page will be shows as per Earning salary (actual value) along with Projected Salary.