3 answers
Thank you, @Jeffrey Chung.
Recalculating the batch did not clear out the Previous Levels. Which I think makes sense. I also tried uploading Null values into Previous Level in a sandbox and that didn't do it either. My next attempt will be unselecting Previous Levels on each Level definition record since it isn't required. Then clear out the values with Null on contacts and see if that sticks. Then re-configure Previous Level. I will keep you all posted on how that goes.