If Tennessee only has 1 loss and it's to Alabama in the regular season, we're in. Here's why...because that means we will have won the East and made the SECCG and won that.
If Tennessee only has 1 loss and it's in the SECCG, we're in. Because that means we beat everyone in the regular season, went to Atlanta ranked #1 or #2 (probably #1) and there's no way we fall below 4. Precedent says so.
If Tennessee has 1 loss and it's to Georgia, it probably depends on what happens in the SECCG. If Georgia beats Bama, Tennessee is in.
If Tennessee has 2 losses, it would be a less that 50% chance, but could happen. I don't see 3 SEC teams making it, so one of Georgia or Bama would have to have 2 or more losses and be left out.
So yeah, your % are probably correct.