Since we have a real, live reporter here - I also want to mention that I've seen a number of reports and such with conflicting information. I've seen Steven is 5'8", 5'10" and the poster I have now from Project Jason says 5'11". I've also seen reports saying he went missing 12/13, 12/14 and 12/15. There are more, but you get the gist.
I sure would love to see these details nailed down.
With descriptive details, always go with what's on the poster. We end up writing 500 stories a day and little mistakes make it through the cracks (see my map issue above...)
As far as the dates: Sometimes, especially early on in a story, details get reported that might not be totally correct. We try to parrot what police or family tell us, but they might not know 100%. They say a detail anyway, and we end up running it. There's a good Las Vegas example of that from today. Remember the shooting at our federal courthouse? Police made a major correction of facts today surrounding that shooting. The victim fired his weapon (originally he didn't), the suspect was shot several times (originally it was twice). You get the idea.
In this case, we all have established from the family and security video that he went missing on the 13th.
Hope that helps. I'm happy to answer any other questions.