Yes, this is what you should expect. You need to be strong and just be consistent in what you continue doing. Obviously you had it right, you saw the difference almost over night. Keep that in mind and just keep with it. They are like kids. They LOVE structure but will test it every once in a while. Heck, Cutty who is my good boy (7years old) gets grumbly here and there and can do his alligator snaps if I bust him. Never would he bite but he is mouthy at times, and he is my good boy. Don't think of rehoming now, just focus on the progress. It took a good 6 months to get miila in line with no more fighting. I still remember the last fight her and Cutty had when I was so exhausted I told my husband maybe she would be better off somewhere else. I worried about the kids being in the wrong place when a fight broke out. Thank gawd he was the calm one who said no, she is a good girl. It was her last outburst and she has been in the pack ever since.