diff --git a/org.adempiere.base/src/org/compiere/model/MOrderLine.java b/org.adempiere.base/src/org/compiere/model/MOrderLine.java
index 4126920d38..952d216f9e 100644
--- a/org.adempiere.base/src/org/compiere/model/MOrderLine.java
+++ b/org.adempiere.base/src/org/compiere/model/MOrderLine.java
@@ -1019,12 +1019,19 @@ public class MOrderLine extends X_C_OrderLine
 	{
 		if (!success)
 			return success;
-		MTax tax = new MTax(getCtx(), getC_Tax_ID(), get_TrxName());
-        MTaxProvider provider = new MTaxProvider(tax.getCtx(), tax.getC_TaxProvider_ID(), tax.get_TrxName());
-		ITaxProvider calculator = Core.getTaxProvider(provider);
-		if (calculator == null)
-			throw new AdempiereException(Msg.getMsg(getCtx(), "TaxNoProvider"));
-    	return calculator.recalculateTax(provider, this, newRecord);
+		if (getParent().isProcessed())
+			return success;
+		if (   newRecord
+			|| is_ValueChanged(MOrderLine.COLUMNNAME_C_Tax_ID)
+			|| is_ValueChanged(MOrderLine.COLUMNNAME_LineNetAmt)) {
+			MTax tax = new MTax(getCtx(), getC_Tax_ID(), get_TrxName());
+	        MTaxProvider provider = new MTaxProvider(tax.getCtx(), tax.getC_TaxProvider_ID(), tax.get_TrxName());
+			ITaxProvider calculator = Core.getTaxProvider(provider);
+			if (calculator == null)
+				throw new AdempiereException(Msg.getMsg(getCtx(), "TaxNoProvider"));
+	    	return calculator.recalculateTax(provider, this, newRecord);
+		}
+		return success;
 	}	//	afterSave
 
 	/**
diff --git a/org.adempiere.base/src/org/compiere/model/StandardTaxProvider.java b/org.adempiere.base/src/org/compiere/model/StandardTaxProvider.java
index 1b55e21931..a508cc3250 100644
--- a/org.adempiere.base/src/org/compiere/model/StandardTaxProvider.java
+++ b/org.adempiere.base/src/org/compiere/model/StandardTaxProvider.java
@@ -79,7 +79,7 @@ public class StandardTaxProvider implements ITaxProvider {
 				for (int j = 0; j < cTaxes.length; j++)
 				{
 					MTax cTax = cTaxes[j];
-					BigDecimal taxAmt = cTax.calculateTax(oTax.getTaxBaseAmt(), order.isTaxIncluded(), order.getPrecision());
+					BigDecimal taxAmt = cTax.calculateTax(oTax.getTaxBaseAmt(), false, order.getPrecision());
 					//
 					MOrderTax newOTax = new MOrderTax(order.getCtx(), 0, order.get_TrxName());
 					newOTax.setClientOrg(order);
@@ -210,7 +210,7 @@ public class StandardTaxProvider implements ITaxProvider {
 				for (int j = 0; j < cTaxes.length; j++)
 				{
 					MTax cTax = cTaxes[j];
-					BigDecimal taxAmt = cTax.calculateTax(iTax.getTaxBaseAmt(), invoice.isTaxIncluded(), invoice.getPrecision());
+					BigDecimal taxAmt = cTax.calculateTax(iTax.getTaxBaseAmt(), false, invoice.getPrecision());
 					//
 					MInvoiceTax newITax = new MInvoiceTax(invoice.getCtx(), 0, invoice.get_TrxName());
 					newITax.setClientOrg(invoice);
@@ -336,7 +336,7 @@ public class StandardTaxProvider implements ITaxProvider {
 				for (int j = 0; j < cTaxes.length; j++)
 				{
 					MTax cTax = cTaxes[j];
-					BigDecimal taxAmt = cTax.calculateTax(oTax.getTaxBaseAmt(), rma.isTaxIncluded(), rma.getPrecision());
+					BigDecimal taxAmt = cTax.calculateTax(oTax.getTaxBaseAmt(), false, rma.getPrecision());
 					//
 					MRMATax newOTax = new MRMATax(rma.getCtx(), 0, rma.get_TrxName());
 					newOTax.setClientOrg(rma);