I can olny say from our experience, that he's really changed into an unpredictable we thing recntly. The thing that worries me is the aggression - mostly to me, or Indie. Out of nowhere, he will suddenly turn into this biting, barking, angry dog, will no provocation whatsoever. He's peed on our bed twice, despite not being allowed on our bed, he's bitten m, he will be at my feet having a tummy tickle and will suddenly bite, etc. He's been really aggressive with Indie - we have had to separate them a lot recently, before one gets hurt, and it's horrible.
Play fighting I'm used to, they can make awful sounds then, but this is much more real.
He didn't come to us a well trained dog, and having left things till he was settled down, he's now been going to an apdt training class for four weeks, and is loving it. He's keen to learn, his recall is fabulous - he's such a quick learner, I will be booking another course after this and just keep going with him, because he adores it and is smart as a whip.
Indie went through the ten stage, forgot verything he'd learned, forgot recall, humped a few times, but not the aggression or peeing stuff.
I don't have enough experience of dogs to know 100% if it's the right thing, but my trainer thinks it is, and also Hamish's vet (one of the few that haven't tried to push the issue), so I'm going from that, and also reading up on what I can.
Mind you, still haven't booked him in yet