When setting up a summary reconciliation filter, what does "Balance Exists" represent?

I'm setting up a summary reconciliation filter for a Variance Analysis reconciliation (screenshot below). One of the filter options is "Balance Exists." What does "Balance Exists" represent for a Variance Analysis reconciliation? If a balance exists for the current period or the variance period, will that individual rec roll up into this summary rec? Or does balance exist represent just the current period balance? Does balance exist mean the balance does not equal 0 and is also not blank? Also, does this take into account balances loaded through Data Exchange and pre-mapped balances manually imported directly to the reconciliations?