Add lost comments about decay playing a role in guaranteed Stable flag assignment guaranteed familiarity

In 8bf1a86a we removed comments related to potential decay rates when e.g. Stable guarantees. The problem now is that in that case the spec has a different number ("7") than the code ("5") without explanation whatsoever. Let's get those comments back and then at some point think about how to get the decay concept into our specs as well.