Average cost to hire a owner operator to haul grain with a end dump?

What is the grain? Assuming this is corn and the trucker is able to do two rounds a day at a 1000 bu seems pretty close. I have a neat spreadsheet built for those trying to figure rate. My primary job is transportation ,and I would like to build my spreadsheet into an app. For all customers, owner operators to use and dial in, biggest mistake is to not include all variables.