I'd contact heavy16 there good about getting back to people about there products. I know when it first came out a few years ago it was considered to hot and they dialed it back a bit. As far as recent changes, just guessing but I've seen other boosters that contain phosphite have to change there numbers because some states don't recognize phosphite as a phosphorus fertilizer.
That's unfortunate, Bryce has always returned all my e mails, it's been a couple years since I've contacted them though. Maybe try to old school it and call them during business hours 877 YO HEAVY