Items with tax implications check box

Hello,

      I have what I hope is a simple question. On the expense type setup page there is a section, Tax Related Indicators. In this there is a check box, with Items with Tax Implications.  What exactly does this box do?  I have looked, but other than indicate that expense type is a taxable item, I do not see anything.  My customer believes that this will send data to Payroll, but I do not see any indication of that.  Any assistance will be appreciated.  Thank you.