^ Yeah, and notice that when I said that was the "right approach" I was also agreeing with the idea that there would still be room for reasonable disagreement on whether the call of something being a mistake is the right one. And this is exactly why production notes might be important, as they might [if they exist] shed light on why the number changed from 12 to 5. My guess is that it's just one of the things that fell through the cracks. I'm perfectly comfortable with the idea that the Enterprise from the early episodes just ends up existing in a slightly different reality than she was in all later episodes. This is a far more realistic approach than proposing convoluted explanations for all the inconsistencies. Yeah, it was actually 12. http://en.memory-alpha.org/wiki/Constitution_class_decks. TMoST does not mention deck 12.