The 13th Month Salary......

The 13th month salary theory states that you get paid twice on the 12th month because there is no 13th month.................... Do you work in a firm where the 13th month is paid?.. When i was in Encomium Magazine we used to get paid the 13th month and i remember how shocked i was when i received my first 13th month salary...I thought the accountant had made a mistake so i went back via IFTTT