I have created a PL SQL function to calculate amount based of rates stored in the database for different period, The function is supposed to iterate through given month and get the rate of each month and do calculation for all months and obtain the total amount for all month as the result.
Unfortunately the function display different results when run in different computer with different data format. Could i be missing the calculation of months in the logic?

This is the PL/SQL function to calculate amount based on different rate stored in Database declare the function and the amount it accepts