Why in Update average cost form is picking the same adjustment account?

I try to update the average cost of an item using Update Average Cost form. I have entered the adjustment account in the header level and once I entered the Item code, rest of the accounts such as Material, Material Overhead, Resource, Outside Processing, Overhead account automatically select the Adjustment account which I entered in the header level.

Why is it happening?

EBS version = R 12.2.12