When you set a Master Filter, the Analyzer will find any and every entry (row) of flight log data that has the master filter column value > 0. For example, when you set the master filter to Dual, the Analyzer searches your logbook for all entries with 'Dual > 0'. If you have any flight log entries with a Duration of say 1.0 and Dual of 0.5, you'll get a disparity. An easy way to see if there are differences, for example with PIC and Duration is to go into the Spreadsheet Style log and click the PIC column header which will force a sort on this column. You can even drag the column to be to the right of the Duration column so they are side-by-side for comparison. See if there are any rows of data where the PIC and Duration do not match.
If you like, send a BACKUP (.BAK) to firstname.lastname@example.org
and I'll gladly take a look.