Because of the way DVC is sold, contracts represent a real estate interest in a specific timeshare unit. At any given resort, points from two units may both be a June UY, but contracts cannot be combined as each contract represents a % interest of their respective unit which, once declared, cannot be changed.
This (unit number) is also a factor in Disney's ROFR decisions. IMO, it's the main reason we have been unable to establish any kind of reliable "pattern" for those decisions.