If a Publication is updated in the Publications Manager, existing print coverage will not be impacted.
Why?
Let's say a piece of print coverage is added to a report. At that time, the circulation of the Publication is 100,000.
One year later, the Publication has a circulation of 50,000. The Publication is updated. However, the Circulation 12 months ago was still 100,000. Therefore the historic print coverage is not updated.
To update historic coverage, simply re-add the Publication and the new figures will be applied.