optimised tei:seg (total net time cut by half)

Change-Id: I4d7f7c8c844200c38366dd00f6c34dfaf5c6c877
diff --git a/nkjp2korap.xsl b/nkjp2korap.xsl
index 8aef8b9..64b65e1 100644
--- a/nkjp2korap.xsl
+++ b/nkjp2korap.xsl
@@ -501,10 +501,7 @@
       constituent values, should anything go wrong; it might get compacted at some point, but 
       the increase in efficiency will probably be minimal, compared to the decrease of readability   -->
     <xsl:variable name="offsets" as="xs:integer+">
-      <xsl:variable name="akku"
-        select="map:merge(tail(fn:accumulator-after('elem-offset-seq')), map {'duplicates': 'use-last'})"
-        as="map(xs:string,xs:integer+)"/>  <!--test later if the merger is really needed here, given how accus work-->
-      <xsl:sequence select="map:get($akku, string(@xml:id))"/>
+      <xsl:sequence select="map:get(fn:accumulator-after('elem-offset-seq')[last()], string(@xml:id))"/>
     </xsl:variable>
     <xsl:variable name="my_name" select="local-name()" as="xs:string"/>
     <xsl:variable name="my_id" select="@xml:id" as="xs:string"/>