It seems to me that I heard someone say that it can be "up to" ten movies. I'm with you. There aren't ten movies worth nominating; but, I don't think that will stop them from nominating some movies that no one outside Hollywood would want to see.
As to these nominations from SAG: Go Game of Thrones!
Read the artical at my link on post#14. Key sentences ===> The Board voted to institute a system that will now produce anywhere between 5 and 10 nominees in the category. That number won’t be announced until the Best Picture nominees themselves are revealed at the January nominations announcement.