"Sum of Amounts" compartmentalizes the qualifying items that may receive a % off discount. It adds up the subtotal amount of all qualified items in the Line Item Filters and applies the discount to only the sum of that amount, not the whole check.
Leaving the Line Item Filters blank defaults to the Sum of Amounts, meaning that the % discount will be applied to the sum of all items on the receipt or all items in the Line item Selectors (LIS) added under Item Qualifiers.
If Line item Selectors (LIS) are added under Line Item Filters it will discount the items based on the function attached to this inline function (i.e, Maximum unit price, Minimum Unit price or Exclude) and not the subtotal amount of the entire receipt.
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