I am not sure why Sharkbait but you could ask him the question. My own personal take is that he is planning to release his Kursk mod in February and he wants to see what the public response is to his proposal (I 'd call it Pay 'n Play.It sounds so American
). Perhaps he also wants to make sure those interested and who paid don't have to wait too long to get the goodies!
As for those who don't pay before 31/01/2010, I guess either they won't get the full package or may be some of the benefits coming with membership or technical support or even discount or free future mods or releases. But it's just a personal guess; only ZW knows what his own plans are.