This option refreshes part of the Scores worksheet -- the part where the correlations appear, which is always at the bottom of the worksheet.
You might want to use this option after you have deleted one of the columns in the Scores worksheet. When a Scores column is deleted, the correlations become messy, with Excel tending to display REF# messages, or something equally ugly. Updating the correlations via this option will clean things up.
Remember that deleting rows in the Scores worksheet is a big no-no. If a row is deleted, Lertap loses track of what's what in terms of the data, and who's who.
You may delete the whole Scores worksheet, and you may delete one or more columns of scores without affecting Lertap's internal data structure. But don't delete any of the rows, okay? Promise?