Dodge warrantees our 2012 Dually not Cummins. Cummins may say the engine is capable of using B20 but Dodge says no more than 5%. So we will follow what Dodge says since the truck is still under warranty. And a gas truck is not an option. We even checked with Dodge about converting our truck to be B20 capable but it would cost us more than a new truck. So we will have a decision to make about purchasing a new truck or just avoiding states that primarily sell bio diesel. But it seems much of the Midwest is going the bio diesel route and that is a lot of states to avoid.