I am correcting my post as I think the answer is in this link,
https://www.etrailer.com/Propane/JR-...207-30325.html
This is the sentence that I read:
Regulates 500,000 Btu/hr or 30 psig based on 100 psig inlet What the 100 psi is, just a reference, so that at 100 psi inlet pressure, the regulator will provide 30 psi outlet pressure. That isn't a maximum pressure rating. So, at higher inlet pressure, the regulator outlet pressure will be higher going to the regulator on the other side of the trailer, but will still be quite a bit less than cylinder pressure so the gas will not re-liquify in the crossover pipe, which is the purpose of having that high pressure regulator.