FWIW, I don’t think that’s why they’re waiting. OR apparently has mandatory minimum sentencing for first degree arson. Et they’re trying to find a way around it, or just outright intend to ignore it and let her walk when they hope nobody’s notice.
Yes, they could continue her arson sentencing until they drop it altogether but that’s usually done for a charge not a plea. I don’t know how it is in OR tho. In any event her life sucks right now and will continue to for years regardless if she goes to prison or not.