What is Sum Column tick box?

[Biju]

HEM1. Tourney - Results - Data View, Tournament summary window in top half of window the second column after the Tournament number is a tick box titled Sum. Until recently this has always been ticked and I presumed it was Finished Tourney box. However lately these are unticked and if I double click the Tournament the Tourney Finished box is ticked. What is it? Is it important it is now appearing unticked?

[udbrky]

This shows that the tournament summary is imported.