How do I show the inventory value in Item Record but the currency will be in Secondary Book currency?

I created a custom field for Item Record and in the Custom Item Field Record, under validation and defaulting, I selected a saved search

But after I create this, when I check the item record, there is no value in the custom item field.

The saved search is like this:

type: transaction

criteria:

account is Inventory Asset

Multi-Book Accounting Transaction is Secondary Book

results:

Multi-Book Accounting Transaction : Amount (sum)

filter:

item

UPDATE: I have found why it is not working. There's a field in custom item field record called 'field'. I originally selected a value for this field but for my case I should leave this empty. So when I updated the custom item field record, my field is not correct.