Dingy, I of course do not know, but suspect they got a good deal on a quantity of that steel type and figured they could offer it to us at a better price than the normal steel they use. I reckon the price increase proves that to be at least partly correct. BUT the real (or whole) reason we will probably know.
BUT we CAN all rest assured that "The Boys" will always do their best to give us the Best possible prices they can. That's just the kind of boys Mrs. "B" raised, God Bless her.