no, you shouldn't even began to use scrolls in the treasure from the start since orochimaru is easy to gain in chase/survival (i'm at 75 fragments of him for free in 10 months) and Ao is a common ninja in kage treasure. In 1 year of playing is almost sure that you get him for free (if you are lucky, like happened to me, you get him for free at your 4th month).