3818446 - Why Amount Formula is not working if Entry is itemized?

We configured Amount Formula to a custom field, when the custom field amount is less than Transaction Amount, it will cover the transaction amount. However, we found it's not working for the Expense types who enabled Itemization feature.

For example, the transaction amount of a Hotel entry is 180 USD, only 150 USD in it should be reimbursed by company, user has entered  150 in the customized field, however, after save entry, the Transaction amount is still shown as 180USD.

We configured Amount Formula to a custom field, when the custom field amount is less than Transaction Amount, it will cover the transaction amount. However, we found it's not working for the Expense types who enabled Itemization feature, why? , KBA , CON-CA-ADM , Administration , Problem