its like someone copy pasted supplemental material because they didnt know where else to put this information. it's related to costing, but not in the way the rest of the course material is. like, at all. it ruins the flow of the entire course. it shouldve been added to the end, if not in a different course altogether. its like walking up a staircase but midway you have this rock wall climbing structure instead of steps, then back to the staircase.