5. "Cooperative member" shall mean any member of a "cooperative" as defined in subdivision (c) of section three of the cooperative corporations law, which operates a distribution center from which members purchase grocery products, including prepackaged food and non-food products such as paper products, soaps and detergents for resale and whose members sell cigarettes at retail through fifteen or more separate establishments in New York state. In order to qualify as a "cooperative member" for the purposes of this article, a dealer must share in the profits and losses of the cooperative and must have purchased at least twenty-five percent of the merchandise it purchased for resale during the preceding three months from such cooperative, excluding cigarettes and petroleum products. Such volume of purchases shall be measured by the amount paid for such merchandise, prior to any patronage dividends or refunds based on patronage. The registrations of those cooperative members registered as chain stores prior to the effective date of the chapter of the laws of nineteen hundred ninety which added this paragraph shall not be revoked by reason of their failure to meet the twenty-five percent purchase requirement, the requirement that a cooperative member belongs to a cooperative which operates a distribution center or the sharing in the profits and losses requirement of this paragraph five, and upon each successive reregistration pursuant to section four hundred eighty-nine of this chapter, such cooperative members shall not be subject to such requirements, but shall be subject to all other requirements of this article.