I have looked at your post a couple of times but did not answer because I use Excel versus Open Office.
Although many of the functions are similar there are a few differences.
So I will hazard the thought that "Auto sum" is somehow involved.
Open a new blank spreadsheet and create a "set of numbers" . And establish another cell where the end total is calculated.
Then explore "auto sum" or other similar functions to discover a check box or other option that automatically calculates the sum in the bottom status bar.
May be some associated "property" of the status bar.
Try googling words and phrasing such as "OpenOffice auto sum status bar".
I found a number of links. For example...