30% is possible on a B. Look at the Winnebago ERA, most list it at 115,000 and one dealer that we all know will quote you 85K on the phone with little of no haggle.
Do the math that's 30%
Furthermore saying a "dealer" knows that B'S are hot sellers and can get the price is a ludicrous statement. Remember the dealers have an UNLIMITED supply of product in fact dozens of units leave plants all across North America daily.
What is more RARE than class B's are people willing to buy them, and dealers know that.
They also know RVers will travel from Florida to California to Canada to shop and pick up their vehicle.
305 is where you START you can ALWAYS go down from 30% but you can never go UP from 20%