I didn't think the STS was that much different over in Europe but perhaps it is. Over here in the northern wheat belt, the STS is completely out of its element and is at the back of the pack when it comes to hard thresh wheat. I've always found the lexions did a great job, whether the wheat was easy or hard thresh, and was easy to dial the machine in. As for this 580R, do you have the correct APS grates installed and_or the disawning plates closedIJ Remember that even with the disawning plates closed you can still thresh or pre-thresh with the small grains grates installed. You can install filler bars, easy to do, but I don't think you'll have to with the right concave and cylinder speed setting and APS working for you. Also wouldn't hurt to verify that concave is set properly front to back and left to right.