The Final Five models - Tigh, Tyrol, Tory, Anders & Ellen are fundamentally different in that, among other ways, they do not have model numbers.

So, why skip from Six to Eight? If none of the Final Fives is designated a Seven, then why aren’t Sharons called Sevens?

Of course, the obvious answer is that the Sharons were designated number Eights before the behind-the-scenes Powers That Be wrote it into the storyline that the Final Five do not have numbers.

Well, obviously, in the Cylon religion, seven is a cursed number. Thus, the Cylons skip it when numbering their models, just as we sometimes skip ‘unlucky thirteen’ when numbering building floors.

They boxed the sevens. It’s the only explanation I can come up with that makes any sense at all. I mean, when they boxed the threes, it didn’t appear to be the first time they’d ever done it.

When Sharon cuts a hole in her palm and jams an optical computer cable into it, that leaves her with one functioning hand. So unless she takes her boots off, she can’t count higher than seven.

The 3s were the first time the Cylon’s boxed an entire line. Before her only individual Cylons had been boxed. The reason for the bizarre model numbering is that Ron Moore is making all this up as he goes along. Sharon was identified as an 8 before he even came up with the idead of having the Final Five being seperate from the other Cylons.

Yep. The writers have admitted that they never expected to make it past the second season, so they didn’t bother to think that far ahead. They laid enough groundwork in season 1 that when they got the green light for season 2, they were able to come up with enough plotline for a second season, but when they got the green light for season 3, there was kind of a universal “uh-oh… now what?” feeling. For all we know, the Final Five or So have nothing to do with the numbering system, and they’ve boxed all the 7’s and the 9-246’s, and the seven we know about are the only ones left.