diff --git a/org.adempiere.base/src/org/compiere/model/MInvoiceLine.java b/org.adempiere.base/src/org/compiere/model/MInvoiceLine.java
index 64c246e4aa..7e319aaa1f 100644
--- a/org.adempiere.base/src/org/compiere/model/MInvoiceLine.java
+++ b/org.adempiere.base/src/org/compiere/model/MInvoiceLine.java
@@ -432,7 +432,7 @@ public class MInvoiceLine extends X_C_InvoiceLine
 			return;
 	//	setLineNetAmt();
 		MTax tax = MTax.get (getCtx(), getC_Tax_ID());
-		if (tax.isDocumentLevel() && m_IsSOTrx || getTaxAmt().signum() > 0)//	AR Inv Tax
+		if (tax.isDocumentLevel() && m_IsSOTrx)		//	AR Inv Tax
 			return;
 		//
 		TaxAmt = tax.calculateTax(getLineNetAmt(), isTaxIncluded(), getPrecision());
diff --git a/org.adempiere.base/src/org/compiere/model/MInvoiceTax.java b/org.adempiere.base/src/org/compiere/model/MInvoiceTax.java
index 8187b0c8e1..d1eee99490 100644
--- a/org.adempiere.base/src/org/compiere/model/MInvoiceTax.java
+++ b/org.adempiere.base/src/org/compiere/model/MInvoiceTax.java
@@ -209,7 +209,7 @@ public class MInvoiceTax extends X_C_InvoiceTax
 				//
 				// phib [ 1702807 ]: manual tax should never be amended
 				// on line level taxes
-				if (!documentLevel && amt.signum() != 0)	//	manually entered
+				if (!documentLevel && amt.signum() != 0 && !isSOTrx)	//	manually entered
 					;
 				else if (documentLevel || baseAmt.signum() == 0)
 					amt = Env.ZERO;