Iryrob9301, that sounds like the most sensible way to do it and not cause delay at the pumps for other people. And, you can get the best price as the OP wants to do.
Our coach will have the DEF and Fuel filler together around mid coach on the driver's side. Originally on previous Prevost models, the DEF was located at the passenger rear and Prevost moved it to the driver's side. Since DEF is not required at every fill up, your procedure sounds good for those with the DEF filler located on the passenger side.
MM.