While I felt like others here, encouraged that the PB is engaging and agreeing, etc, I'm going to continue my somewhat gloom'n'doom approach just so you can consider the worst case, as you hope for the best.
It a possibility that the PB is in for another go only because he's been successful so far at offloading some if not all of the redo expenses onto the plaster company. And now he's stating he's going to do that again, only even more of the share this time. And that's great. For him. These are mid-four-figure pops (the replaster expenses) that are not likely going to put anybody out of business. Heck, he might even still be in the black for all we know. But as soon as he catches wind of the complete redo we're all suspecting is going to be needed, now we're talking about a mid-five-figure bomb, and that's when you need to be prepared for him to turn on you. Because he'll have no one to share that expense with, and that could put him under if he's got no liability insurance or bankroll for such a scenario. You can tip toe around this for a while, and stall on the "Call the Board" advice I gave earlier, but if that shell is as bad as we fear, then you're going to be in for a battle. I hope I am dead wrong. But I also hope you're preparing yourself that I'm not.
Just a word about tstex's "3rd party concrete expert" that he keeps referring to. (And BTW, his whole last post is dead on.) May I? You need to stop thinking about whatever expense that's going to be, or whatever delays that might cause, or whatever ill-will that might generate, as "above and beyond" the scope of this project, but instead as the critical part of this construction process you should have incurred, and paid for, all along. The piper is calling... pay him!
This is what I mean: I find it incredible that there's anywhere in this country that you can build a pool without it being properly inspected by a qualified person that is working as your advocate, at least in terms of keeping the contractor honest and holding him to well-established industry standards and codes for all aspects of the construction of a residential pool. Apparently, you live in an area that doesn't require that. But that does not mean that you should not require that. The rest of the "civilized world" has to create plans, engage engineers, acquire permits, have all those plans reviewed and approved, then allow the entire construction process to be subjected to thorough inspections, and redos if the work is substandard. Most, if not all, cities and counties charge for all those plan check and inspection services, like, a lot. Plus all the engineering expenses. Maybe thousands of dollars. You didn't seek out any of those services (no fault of your own, you didn't know to). You didn't pay for them (presumably). And now you're living through the result of that. You certainly could have, you probably should have, and now there's a growing number of your TFP supporters that are telling you that you just have to now. Pony up. Hire your own "inspector" with the money you never spent on one, and from this point forward make sure that all of the existing construction was done correctly, or rip out what wasn't and make sure the remaining construction is done correctly, including, quite possibly, the entire gunite shell.
Otherwise, you're just continuing to rely on a PB and a set of his subs to self-regulate, and to keep trying at something they've already failed at several times, catastrophically, without any oversight, and without any advocate of yours watching out for your best interests, not theirs.
Hiring your own "inspector" (expert) isn't money lost, it's money you should have spent in the first place.
I acknowledge I'm not being particularly sensitive/polite/encouraging. Sorry 'bout that. Seems like we might be past that at this point...