I think you guys are putting your focus on the wrong things. As stated previously by others, the paper could have been purchased months if not years earlier and, could have been purchased at a location completely separate from where he lived and worked. The only significant point is that the Zodiac used Woolworths fifth avenue, one time and, one time only. Law enforcement had asked the Zodiac to provide more details about the crimes. They weren't concerned about his perception of how the events took place as the Zodiac laid out. They were hoping that through his letter writing he would say or do something that would give more indication of who he was and possibly how to catch him. The zodiac may have known this because he uses a paper, one time and, one time only. That paper, Woolworths and/or 5th avenue, is significant to zodiac and the case. Focus should be on that fact.