...and to further confuse things, some chapters using the RFM use "flex" lists which mean they *may* invite additional PNM's to achieve the desired range of accepted invitations per panhellenic guidelines. It can get very confusing and depends on the individual chapter as well as the campus panhellcnic.
Look, it's easy to over analyze this. If you're going through recruitment, do it with a good attitude and an open mind. What is your second (or third or fourth) choice today may be your #1 choice tomorrow.
It happens ALL THE TIME. Maximize your options, attend all parties to which you are invited and try to enjoy the process. Digging into this minutiae can only make you crazy! (plus it gives you wrinkles and you don't need that!)