You can choose either the beginning or middle of the month for monthly withdrawal (I have both with two different use years). The first withdrawal of the year in Jan is always in the middle of the month. I am not sure what you are looking at on your statement What you might be looking at is the Payment Due date which is Jan 15. That is reference to the due date for the entire year's dues if you don't have automatic withdrawal from your account. Officially, everyone's dues are due on that date but your separate agreement for monthly witdrawals means you pay in installments over the year. There is a separate section at the bottom that shows when monthly payments are due. If yours says the fifteenth for every month then somehow yours got changed and you might call MS accounting to inquire.