How he gained only 3 levels from killing the 'Professor'. He gained 120k XP from it and it seems it was 30k 31k 32k needed for the level ups. His current XP should be higher.
Correct me if I am wrong but it was Emmy who caught Erwin, which means she is a liability to Asher. I hope to see Asher dealing with her in the next chapters. Thanks for continuing writing.