formula coulmn used in another column issue in XML Data template in BI publisher

Hi All,

XML Data template code:

	<properties>
	<property name="xml_tag_case" value="upper" />
	<property name="include_parameters" value="false"/>
	<property name="include_rowsettag" value="false"/>
	<property name="debug_mode" value="on"/>
	<property name="db_fetch_size" value="200"/>
	<property name="scalable_mode" value="on"/>

    </properties>

<element name="INV_TAX_AMOUNT" FUNCTION="SUM" DATATYPE="NUMBER" VALUE="G_CF_HAS_DLD_LINE.LINE_TAX_AMOUNT"/>

<element name="line_tax_amount"  dataType="number"  value="line_tax_amount"/>  in G_CF_HAS_DLD_LINE group

  FUNCTION Line_tax_amountformula( line_type            IN VARCHAR2,

                                   line_extended_amount IN NUMBER )

  RETURN NUMBER

  IS

  BEGIN

      IF line_type = 'TAX' THEN