Does being awarded a 13 week protection on my rent charge mean its going to be back dated

had a letter from housing benefit saying "you have been awarded a 13 week protection on your rent charge from 02/08/2010 to 31/10/2010 because you was able to afford your rent when you moved in and have not received housing benefit within the past 52 weeks.for this period your housing benefit will be based on maximum eligible rent of 150 pounds" does this mean im getting 13 weeks money?

Doesn't make sense to me either. Call the people that sent the letter and ask them what that means.