A trip in March 2014 will fall in your Aug 2013 UY. You could not use August2105 points for a March 2014 trip. You could use banked Aug 2012, borrowed Aug 2014 or current Aug 2013.
If I am understanding what you want to do correctly, the answer would be no. March 2014 would be under your August 2013 UY points as the current year, and you'd only be able to borrow from August 2014 points. Unless I'm misunderstanding something! Hoping someone else can confirm?
I have never borrowed this far in advance but did see under my account that 2015 points were available to borrow. But probably for reservations
after August 1st, 2014. I think that makes more sense.