Unit cost greyed out when creating an Adjust Inventory reducing the quantity of an Inventory Item

The Adjust Inventory page, unlike Adjust Inventory Worksheet, adds/deducts the adjustment from existing quantity and valuation. For this reason, users creating a "negative adjustment" (i.e. reducing the existing quantity) means they are reducing their inventory quantity from existing stock, thereby effectively using its existing value - hence the system will prevent users from using a different value by exposing the Unit Cost field as an inline text/greyed out value.

This is different from increasing the current quantity where users can enter new cost for the quantity added (just like having a different acquisition cost when purchasing the item).