Taxable Income in Year End Workbench not matching Tax History

Hello,

I am trying to understand how the field AFDWG (Employment Income-Year Work bench) is calculated because I have a discrepancy of about  6,000 dollars between the amount displayed in this field and the information displayed in Canada Tax History Inquiry - Pay & Taxes By Month. I have search in the table F0618 and the amounts there match the Tax History and I do not see anything in table F0719 that should be added to income that amounts for the discrepancy.

Thanks.