It's one of the things that changed with our automated release. It even changed from our initial announcement, when we still wanted to have semi-static pool assignments. Over time we came to realize that this was a much more elegant solution code-wise and when we eventually fit our accounts to our SP curve goal it will result in a similar outcome (semi-static pool assignments).

I'm happy to talk about how that outcome will eventually happen if you're interested, but it gets pretty technical.