I hadn't noticed 8900 as being one of their magic

I hadn't noticed 8900 as being one of their magic numbers but I'll take your word for it. They DO use numbers as signals -- someone who used to be a junior market maker told me this years ago. And we have observed it.

This time, they started with a 10,000 share ask, so the 8900 might be coincidence. But, with these guys, the chances of coincidence are slim.