How can I recursively summarize grouped by nodes?

Hello,
 I have the following XML:
<nodeList >
<node group="chassis" instanceName="7604-RSP720C-P" unitPrice1="60" discount="0.0" quantity="1.0">
            <node instanceName="2700W-DC" unitPrice1="100" discount="0.00" quantity="2.0000" />
            <node instanceName="RSP720-3C-GE" unitPrice1="100" discount="0.00" quantity="3.0000" />
      </node>
<node group="chassis" instanceName="222222222" unitPrice1="100" discount="30.00" /uantity="4.000">
            <node instanceName="1C" unitPrice1="N/A" discount="0.00" quantity="5.0000" />
            <node instanceName="2E" unitPrice1="N/A" discount="0.00" quantity="5.0000" />
      </node>
<node group="chassis" instanceName="333333333" unitPrice1="N/A" discount="0.00" quantity="6.0000">
            <node instanceName="1C" unitPrice1="N/A" discount="0.00" quantity="7.0000" />
            <node instanceName="2E" unitPrice1="N/A" discount="0.00" quantity="8.0000" />
      </node>
</nodeList>

what i would like to do is to summerize the total price of each group and the total price of all the groups (all the nodes).

I managed to count the sum of each group by using the following code:

 <xsl:template match="NfxML/body/nodeList">
 <xsl:for-each select="node[count(.|key('contacts-by-chasi', @instanceName)[1]) = 1]">      
     
          <xsl:variable name="GroupName" select="@instanceName"/>
          <br /><xsl:value-of select="$GroupName" />:
                     <xsl:variable name="TotalSum">
                             <xsl:call-template name="calculator">
                            <xsl:with-param name="curSum">0</xsl:with-param>
                            <xsl:with-param name="counter"><xsl:value-of select="count(descendant-or-self::*)"/></xsl:with-param>
                    </xsl:call-template>
             </xsl:variable>

             <xsl:value-of select="$TotalSum"/>
      <br />
</xsl:for-each>
 </xsl:template>

  <xsl:template name="calculator">
    <xsl:param name="curSum"/>
    <xsl:param name="counter"/>

   
    <xsl:variable name="qty" select="number(descendant-or-self::*[number($counter)]/@quantity)"/>
    <xsl:variable name="cost" select="number(descendant-or-self::*[number($counter)]/@unitPrice1)"/>
    <xsl:variable name="discount" select="number(descendant-or-self::*[number($counter)]/@discount)"/>

    <xsl:variable name="sum" select="number($cost*(100-$discount) div 100 * $qty)"/>
   

    <xsl:variable name="CycleSum">
     <xsl:choose>
        <xsl:when test="string(number($sum)) = 'NaN'">
              <xsl:value-of select="number($curSum)"/>
        </xsl:when>
        <xsl:otherwise>
                <xsl:value-of select="number($curSum + $sum)"/>
        </xsl:otherwise>
      </xsl:choose>            
    </xsl:variable>    

    <xsl:choose>
      <xsl:when test="number($counter - 1) > 0 ">
           
        <xsl:call-template name="calculator">
          <xsl:with-param name="curSum"><xsl:value-of select="$CycleSum"/></xsl:with-param>
          <xsl:with-param name="counter">
            <xsl:value-of select="number($counter - 1)"/>
          </xsl:with-param>
        </xsl:call-template>
      </xsl:when>
      <xsl:otherwise>
        <xsl:value-of select="$CycleSum"/>
      </xsl:otherwise>
    </xsl:choose>  
  </xsl:template>


 Who can i get the total sum in the most efficient way?

the output I would like to get is:

7604-RSP720C-P: 560
222222222:          280
333333333:          0

Total:                   840