Accepting Consequences

We have been doing the rule of 3 with our 11 year old. The first time, it took her over 90 hours to finish her 24 hour loss of privileges because she kept needing to start over/did not choose to follow instructions. She stayed in instructional control for part of a day but lost her privileges again later in the afternoon. She refuses to do anything for hours at a time, including her schoolwork (we homeschool). She would read for hours to delay accepting her consequences, so we need to keep her sitting close to an adult, which makes it hard to give her sibling the attention she should have. Any tips on how to motivate her to choose to obey? It feels like she just loves to power struggle. She continually tries to steal privileges as well.