Yes, a valve rated at less than half the capacity will not flow as much gas at a given inlet pressure. Very similar to putting too small of a gas flex on a unit. It will restrict the flow.
Originally Posted by Snapperhead
"The bitterness of poor quality remains long after the sweetness of low price is forgotten". --Benjamin Franklin
"Don't argue with an idiot, they will drag you down to their level and beat you with experience". --Mark Twain