The prior authorization got filled out incorrectly on their end. Regardless of coverage-related breaks, the documented baseline weight hasn't actually changed, still sitting at 330.
Something nearly identical happened here, went from 190 down to 130, then the doctor lowered the dose and weight crept to 140, so a request went in to move the dose back up. The office submitted it as a brand-new authorization instead, which naturally got denied. Called insurance directly, and they explained it needed to be filed as continuing treatment referencing the original 190 baseline.
So the advice here is simple, call insurance directly. Give them the full picture and they'll walk through exactly what the paperwork needs to say. If the doctor won't cooperate on getting it right, switching providers is a real option, did exactly that recently.