What Michigan did yesterday was 1. Acknowledge they did something wrong 2. Suggest they used precedent to come up with the voluntary punishment and 3. avoided any punishment bleeding into the B10 schedule and 4. undermined the NCAA's 4 game suggestion/denial.
If the NCAA comes back and says it's not enough, the punishment next year still won't bleed into the B10 schedule. The language they used, and the language Harbaugh's lawyer used against the NCAA comment a week ago, suggests that any further punishments will have to be justified with proof or result in pushback/lawsuit from the school for the NCAA violating their own rules on commenting during ongoing investigations.
So IMO it's genius. We all knew a punishment was coming. This is the least impactful. And I very much doubt the NCAA does anything beyond tucking their tail and giving in at this point.