unit of cost to finished goods not total to all components proplem

Hi guys i have proplem in unit of cost and if you can help me if possible

1-unit of cost to specified item x(fg) not total to unit prices to all components

ex i have it x finished good


y 20 unit cost

z 30 unit cost

it give me 70 to x

2- what expected cost field found in item ledger entry and are this affect in cost and when it will be 0

3-unit cost some times different from item card to finished good items and release production order (production line table)

costing method to standard

4-applied adjust cost bolean field in item ledger entry it is not checked are this will affect in consumption


I make adjust cost -item entries but no benefit can any one told me the way to calculate unit cost of output journal because i notice it is different about that found in item card