Note : Before applying to Production, please test in DEV/QA environments.
Update the FieldDesc Table with below script :
SET ItemTypeField = -1
WHERE TableName = ‘Trade/Item’
AND FieldName = ‘UserAmount1/UserQuanity1’
Storing/Loading the amount data with sign is not recommended. Sign should be represented using DCIP. But there could be requirement where user want to see the signed amount and its available in multiple columns for different calculation needs.