Yes, as stated the pressurized regulator helps maintain fuel flow. If you have 10psi in the manifold it effectively drops your fuel pressure by 10psi. 55-0 is a 55psi difference. 55-15 is effectively a 40psi flow rate. This is why you need to bump your fuel pressure at least the same amount as your boost. Getting a FPR that will do 2-1 or more is common but will be hard for the stock computer to deal with.