Inventory transaction not re-costed correctly

Hi,Per my understanding cost management automatically costs all the inventory,wip,om,po modules, meaning if there is an inventory transaction it should cost it based on the frozen cost(in standard costing). With that said,

I have created an item and specified a (material) cost of $48,which is the frozen cost.

I did a miscellaneous receipt of quantity 14.

When I check  the material distribution, I could see that the account for material cost is hit with 48 * 14 = 672,which is correct.

Then I have added another cost type "Engineer" with material cost totaling $100.

I ran the standard cost update for the above cost type "Engineer" and I could see now the frozen cost for this item is 100.