Please, keep in mind that once you change a query, you actually restart the search.
This means that the collection starts from that moment onwards. As Mediatoolkit is designed to track real-time mentions, it means that we focus on collecting everything from the moment you set up/change/edit queries.
We do not exclude historical data completely, but the most that we can pick up after the edit is up to 3 months back.
If you wish to keep the historical data, we would advise making sure you extract the data in a form of a document or report prior to making a change.