There could be two reasons for why the values on your IR8A form seem to be incorrect.
a. Either: Date for bonus/director fee has not been captured. Proceed to File Generation -> IRAS Employee Details ->and key in the date for bonus and director fees. Make sure that these dates are within the tax year.
b. Or: The tax code for some pay elements have not been tied up correctly. This means that when setting up your pay element, you have not given it a proper tax code. To fix this,
i. Generate report 18 and 14 for comparison. If certain pay elements in Report 14 are missing in Report 18, these pay elements have not been tied correctly to a proper tax code.
ii. In this case, you need to manually calculate the value of each untied pay element for each employee.
iii. Proceed to Payroll Setup -> IRAS Opening Balance -> Fill up opening balance for missing months.