Inventory item storehouse units on MC can be done with units specified to that storehouse on transfers of that storehouse. For this, as seen on the image below, go to Storehouse>Storehouse management to select the item whose storehouse unit is wanted to be changed. The unit of the inventory item is changed to the desired storehouse unit.
After the storehouse unit is changed, it is saved with save. After this stage, on the transfers made this storehouse, the storehouse unit will come up as the selected unit automatically as on the image below.