Prior to this announcement, all 1M context use consumed "extra usage", it wasn't included in a normal subscription plan.

So, I’ve been using opus 4.6 1m since it was fist available to 20x max users daily. What I think has happened is that even in doing so, I have not actually exceeded the plan token limits and therefore haven’t been charged for “extra usage” (just double checked). So, unless there’s a billing mistake or delay, “any usage” != “extra usage” which is what I was always unclear about. I am careful to iterate with claude on plans in plan mode followed by clearing the context and executing. I think I am hovering around the higher end of the smaller window model where I would have otherwise seen auto-compaction run.

Another reason for less token usage is that 4.6 is much better at delegating agents (its own explorer agents or my custom agents) to avoid cluttering the window.