lumber grades

Is warp covered in lumber grade?

Q. We bought some No.1 Common kiln-dried hardwood lumber and it is warped up and down along the length. This cannot be used to make our larger doors, as the pieces we cut will not be flat. The supplier says that warp is not covered in the grades. Is this correct?

Looking at lumber grade and yield data

Q. I was looking at historic yield data for our company and see a slow trend toward lower yield. Without visiting our facility, can you guess what it is? I have a suspicion that the lumber grades have changed.