Check your appliance installation manual.    Some of the appliance regulators steps the pressure down again from line pressure (11″ WC or higher); and some only work as an steady/excess flow control for even supply flow.   The manual should state  what is needed at the appliance regulator.

Thanks edwmax.  I’ll leave it attached to the appliance.  If the gas flow is hindered in any way I know just where to start.