Honestly , I believe your story up until the point when the trainer come out and just bam the horse is all better
What I'm going to put next isn't just for Calming, this is for everyone in general.
Okay I'm going to be the devil's advocate and let you know when my horse began to be cared for by RandysWifey they ran into some Sky-being-a-jerk problems. He's not a jerk but she didn't have his trust then or understand how to best correct his behaviors. But once she figured it out, he became a very good riding partner and he's much more behaved and not a hooligan.
One good session with a trainer on a horse that just needs GOOD HANDLING and BOUNDARIES, will do a world of good.
You and I both know how horses can sense a strong (not physically.. in horse sense) person versus a quiet person or one that has no clue what they're doing.
They may not be cured, but a good session with good timing that the horse understands what they're being asked to do then they can end on a good note, which is what it sounds like from her OP.
I'm not going to scrutinize on time stamps of posts and assume things.. that's too much of a headache for me personally to do.
But I just had to offer my experience. It's not just Sky, I've worked with many 'problem/pushy' horses in a short amount of time (15 exact in my lifetime, which isn't much) and they were behaving much better after just one session. They weren't completely fixed but it sure did end on a good note.