Thinker,
Actually there is a simpler explanation for why the number of anointed might increase which doesn't require any modification to current JW theology.
Very simply, there may be persons that are newly introduced to the religion (truth) who after learning the truth and about the heavenly hope come to feel and believe that they are part of that number and thus should be partakers. This is especially possible in so-called undeveloped lands but even in well established territories.
Theoretically speaking the supposed "sealing" of the 144K in 1935 is INDEPENDENT of current membership as one of Jehovah's Witnesses. Thus a person who is part of that number could be say in Russia or China or some of the Moslem countries and only recently introduced to the truth and started associating with Jehovah's Witnesses as JWs have still to penetrate into lands like these in significant numbers. Therefore, they could be a "new" partaker to be tallied at the official Memorial observance.
This is just an alternative explanation of why the numbers REPORTING could actually increase. I personally do not subscribe to the traditional JW theology in this matter. I also think that unless the 1935 Sealing Doctrine is revised or dropped than we can only assume that very shortly, over the next 2 decades at most that the official number would drop dramatically due simply to biological factors and assumptions about normal life expectancy and human life-span.
Sincerely,
Eduardo Leaton Jr., Esq.