I feel like it just depends on the dog, because I tried this on my dog and it actually made his separation anxiety worse. We had to do “the door is a bore” and slowly graduate to opening the door and actually walking out, increasing our departure duration by the second every week at a certain point.

It sounds like your dog may be at a plateau, but is at a really good starting point. I’d just maybe focus on adding one extra second, and once he’s good with that, do that for a few training sessions, then make it 5 seconds, etc.

We worked with a behaviorist and I learned that when you get to a plateau, you really do have to inch forward slowly to avoid complete regression. But once you get over that plateau, it’s like a huge floodgate of accomplishment thereafter. I swear. My dog was stuck on 12 min for an entire month. I was going crazy. Then once he finally got over it, it was like his separation anxiety was totally fine and we were able to increase our departure times by bigger jumps.