mortgage interest 13 week rule

I signed on JSA after being made redundant and was told that after 13 weeks I would be eligible for help with the mortgage interest. Have since accepted a part time job of 10 hours a week and declared it. I am now coming up to the 13 week mark, however during the Christmas week I was asked to do more hours which I accepted immediately in the hope it may become permanent. I did 26 hours in that particular week so not eligible for my £5 JSA. My question is "will the 13 week re-start or continue from original sign on date" Many thanks for any responses.