This usually isn't a game farmers are concerned with. It isn't one they should be playing late in a crop year when basis appreciation typically flattens out. It's tough for elevators to make money then, even tougher for farmers who may have significantly higher carrying costs and less flexibility about when they ship. The risk of quality deterioration during the summer is very high in some on-farm storage. When deterioration occurs, the farmer is usually not able to blend his way out of the problem.
Shrinkage is usually higher than at the elevator.
Farmers don't want to load out during busy times such as spring planting and wheat harvest. As the end of the crop year approaches, the window of opportunity for loading out becomes limited. A farmer who delays too long may get pushed back into an end of the year basis crash. This can be especially treacherous this year with the big futures inverses. Push your customers to separate the decision to pick a futures price level from the decision to move grain.