diff --git a/erpnext/regional/italy/utils.py b/erpnext/regional/italy/utils.py
index 12f5762..bc8d00d 100644
--- a/erpnext/regional/italy/utils.py
+++ b/erpnext/regional/italy/utils.py
@@ -151,8 +151,7 @@
 						tax_rate=tax.rate,
 						tax_amount=(reference_row.tax_amount * tax.rate) / 100,
 						net_amount=reference_row.tax_amount,
-						taxable_amount=(reference_row.tax_amount if tax.charge_type == 'On Previous Row Amount'
-							else reference_row.total),
+						taxable_amount=reference_row.tax_amount,
 						item_tax_rate={tax.account_head: tax.rate},
 						charges=True
 					)
@@ -177,6 +176,10 @@
 						summary_data[key]["tax_exemption_reason"] = tax.tax_exemption_reason
 						summary_data[key]["tax_exemption_law"] = tax.tax_exemption_law
 
+			if summary_data.get("0.0") and tax.charge_type in ["On Previous Row Total",
+				"On Previous Row Amount"]:
+				summary_data[key]["taxable_amount"] = tax.total
+
 			if summary_data == {}: #Implies that Zero VAT has not been set on any item.
 				summary_data.setdefault("0.0", {"tax_amount": 0.0, "taxable_amount": tax.total,
 					"tax_exemption_reason": tax.tax_exemption_reason, "tax_exemption_law": tax.tax_exemption_law})