Again, you seem to have a different definition of “should”[1]. Nowhere does it state that if you do not mention it when you start the thread, the votes can not carry over.
Of course it’s the RM’s choice. No one has stated that Om’s vote was valid if you refused to carry it over. You said you COULDN’T carry it over. That’s not true. You refused to carry it over. That’s a very different thing. [1]http://www.merriam-webster.com/dictionary/should