The item profile is also used to generate prices used in quotes so not all elements are used in the purchase order section
The following logic applies:
If there is no entry in the METHOD or BUY PRICE LIST then the [buy price] for the item is entered
If Price list is entered as a method, then the price is drawn from the price list specified in the Buy Price list Area.
Note that a price list typically requires a quantity - this quantity is drawn from the line detail on the purchase order.
If this quantity is changed then the system will check if the new quantity will generate a different price and prompt you to override the price
Methods such a lineal metre, square metres etc are not relevant to the purchase order section so the system will default to the buy price.