<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                      xmlns:common="http://exslt.org/common"
                      exclude-result-prefixes="common"
                      version="1.0">

<xsl:template match="/x">
  <totals>
    <xsl:variable name="rtf">
      <xsl:for-each select="contacts/contact[generate-id() =
generate-id(key('by-type', @type)[1])]">
       <temp><xsl:value-of select="count(key('by-type', @type)) *
../../types/type[@value = current()/@type]/@benchmark1" /></temp>
      </xsl:for-each>
    </xsl:variable>
    <benchmark val="{sum(common:node-set($rtf)/temp)}" />
  </totals>
</xsl:template>

<?xml version="1.0"?>
<x>
 <types>
    <type value="1" benchmark1="540" />
    <type value="2" benchmark1="640" />
    <type value="3" benchmark1="740" />
 </types>
 <contacts>
    <contact type="1" />
    <contact type="2" />
    <contact type="3" />
    <contact type="3" />
 </contacts>
</x>

<?xml version="1.0" encoding="UTF-8"?>
<totals>
 <benchmark val="2660"/>
</totals>

I could do the following easily by making a recursive template and
then looping through the contacts, and passing on the corresponding
benchmark value.  But could xsl:key make for a shorter, more elegant
solution?

Instead of performing an addition for each <contact>, could I simply
sum() them at once, somehow?

With the following XML

<types>
   <type value="1" benchmark1="540" />
   <type value="2" benchmark1="640" />
   <type value="3" benchmark1="740" />
</types>
<contacts>
   <contact type="1" />
   <contact type="2" />
   <contact type="3" />
   <contact type="3" />
</contacts>

desired output:

<totals>
   <benchmark val='2660'  />
</totals>

--
Regards,
Mukul Gandhi