Use of an array formula to sum dollar amounts based on date

Dear all:

The attached file includes the problem. I have a list of dollar amounts in column A and a list of dates in column B. In cell E4 I have an array formula which runs through the entire date list and sums all the dollar amounts corresponding to those dates which occur in the month of August (month #8). I need to expand the formula to so that it only adds those dollar amounts which occur in the month of August 2013. The first formula works great, the second is returning a sum of 0.

First formula (working):

{=SUM(IF(MONTH(B4:B17)=8,(A4:A17),0))}

Second formula (not working):

{=SUM(IF(AND(MONTH(B4:B17)=8,YEAR(B4:B17)=2013),(A4:A17),0))}

Month Year Array Sum.xlsx

Works perfectly. Thank you!