It's very nice when a Contest Holder thinks about issues of fairness in ranking like this. There's no rule about it, but it is nice when you rank in the way RetroMetro_Steve has suggested.
I agree that most designers will work with you as far as different versions of the same design and different file formats are concerned, but as far as what a Logotournament designer is required to provide when asked, this is from the FAQ in the Help section:
"Will the winning Designer provide revisions and different versions?
"We recommend requesting all revisions while your contest is running or during the judging mode. Once a winner has been selected the winning Designer will provide an EPS vector file and multiple sizes of JPG through our automated file system. Upon Client request the Designer is required to provide the following logo variations: White Background, Colored Background, Black & White, and Solid Colors. Additional formats can include AI and PNG."