Unique visitor using Custom Variable

Hi Team,

We are using custom variable for capturing few attributes, Irrespective of setting values in all scenarios, we are getting discrepancies in the count of unique visitor (snapshot attached).
we did an export from the ‘Visitor Log’ into an Excel and tried analyzing the data. But still could not figure out “the discrepancy” in unique visitor count.

What is the attribute which we can analyze from the Export to identify this discrepancy? please suggest

Many thanks !!


Any help on this, I just want the factor by which Piwik decides a unique visitor for custom variable so that I can look at the export xls from Visitor log to identify the unique visitor and match the information.