I don't think so. As a Merit source, "hoarding" already means you can send less sMerit in total. If my source is removed at the end of this month, that doesn't make me spend more now. If anything, it would make me more careful with "my own" earned sMerits, as I'll need those to cover the time when my Merit source is put on a dry spell.
Merit is for quality posts and if there are not enough quality posts, source merit can be spent less than before. If the forum changes to be less active in future, consequently in this example, there are less quality posts, so sourced merit monthly can be reduced and can be spent less. It's natural and there is no convincing reasons for dumping sourced merit on non-quality posts just because your monthly countdown timer comes to very last days.
While we will not be directly moderating this, I encourage people to give merit to posts that are objectively high-quality, not just posts that you agree with.