In a year when the Orange Bowl is NOT a semi-final, AND when an ACC team is selected for the CFP, THEN the next highest ranked ACC team fills the ACC Orange Bowl spot. Same for the ACC opponent in the Orange Bow in 2020. It is the highest ranked, non playoff, team from the SEC or BIG10.

Same process occurs for the Rose Bowl (P12/B10) and the Sugar Bowl (SEC/B12) in years when those bowls are not the CFP semi-finals.

For example, if somehow Notre Dame, Clemson and Miami from the SEC were to somehow all be in the top 4 of the final rankings of the CFP this year, then the next highest-ranked ACC team would go to the Orange Bowl, even if that team were ranked well below #20.

This is part of the “guaranteed” spots.

But they can’t simply throw out a higher-ranked team for a lower ranked team for one of the at-large spots. Those go to the highest ranked teams after all the guaranteed spots are filled.