By the time Katie first spoke publicly, she'd had a week to remember the details, not just two days. IMO, if it all truly happened as she said and Sebastian ran away, by that time she would have played the whole scene over and over in her head to try to see if she had missed any signs from Sebastian that he was planning to run away.
You may be right, she may simply be adding details as she remembers them. Although it's a mystery to me why it would take weeks to remember details, instead of a day or two as with your bank robbery victim.
But it's also true that adding details as the story is retold is a sign that someone is lying.
Well yes. I agree, and that's a good point. but I imagine she gave the LE the details the first few days. And that's what matters. They would've gotten all that info. I'd she changed something she told them in the few days in a later interview, you can bet they'd be on her real fast.
But they have said that they have verified everything she told them.
(Source: LE presser/or Nick Beres interview the same day)
but...regardless
I still see no lies there. None of those statements contradict each other.
But, if the first interview was 8 days or so after he went missing and then she gave subsequent interviews, she also could be not realizing how much detail the interviewer wants and knowing that LE or a liason has likely provided her with which details to make sure she shares (his clothes, personality etc) and her focus is on that, plus the stress of losing a child.... then forgetting little details is not a big deal in my opinion. Remember it was the internet that made a huge ordeal and dissected the "noise" and her response. Etc.
It's likely LE took those statements at face value esp after a polygraph where I'm sure she was asked questions about that also. It's just not out of the norm for a 15 yr old to go to bed at 9 and start jacking around in their room.
So that statement probably didn't even seem like a big deal to her at first until the crazed conspiracy wing of internet sleuths (yall know what i mean, not evidence backed) started making it a big deal. And I'm just guessing here, but I would imagine she thought, well crap, let me be clear on that so I'm not accused of lying and so she told all she knew of that night. IMO that's likely.
*also, adding details as a story is told is not a sign of lying if it is EXPOUNDING on the previous info. It's just not. Context always matters.