yeah, this smells like a bug in their (dumb) usage segmentation.

For example, there is a distinction of what is classified as extra-usage-billed VS extra-usage-enabled. As a long time claude user, I can assure you they are different things: to use Sonnet[1m] you are required to have extra-usage enabled, but it won't actually bill it unless you are out of quota. Surprisingly, you can use Opus[1m] without extra-usage enabled (!!!).