I can understand if you ask for the price for the sell and buy price for the same grade. That is business. Change the subject to something else say hay. If you buy and sell you are not going to tell everyone who buys hay from you how much you paid for it.That said the fact that the other grades are so close in prices you can ask for a buy price in one grade and a sell price in another grade. Or just inquire on the trader and you can determine the mark up they charge.
Keith