Hi, Is there a way to track the amount of paid changes without using formula at the invoice level? I would like to track the changes like system notes. What field can be use to track the changes. Thanks.

You could do a search of the Transaction with a join to System Notes. I did similar for a client and used a Summary search with a Summary criteria of Count of the field dates. So if only one System Note date, no changes, a count of 2 or more there was changes.