CFINDEX - Update existing collection with new data - duplicates records

I have a collection made up of a document crawl to index pdf, word, excel etc.

now i need to update the existing collection with meta data related to articles in reference to the documents, however when i run the query to update the meta data the existing records do not get updated, a new record is created

initial index

<cfif isNumeric(idx)><!--- directories named by year e.g.: 2009 are public --->

        <cfset sCollectionName="#aCollectionCreated[1].CollName#">

        <cfindex collection="#sCollectionName#" 

          action="update" 

          type="path"

          key="\\192.168.168.66\media\#idx#\" 

          urlpath="#sFullSeverName#/wp-content/uploads/#idx#/"

          extensions = "#lstValidFileExtensions#"

          recurse="yes"

            postterms_s = "" <--- used in later update --->

            posttermssearch_s = ""<--- used in later update --->

            posttermssearch_t = ""<--- used in later update --->

          >

    </cfif>

which creates about 1800 records

later afrer some manipulation nd cleanup (soem files need to be removed) i run

<cfindex

    query="getTermsMembers"

    collection="#sCollectionName#"

    action="Update"

    type="Custom"

    key="KEY_LOOKUP"

    body="url"

    postterms_s = "terms"

    posttermssearch_s = "terms_search"

    posttermssearch_t = "terms_search"

>

i have confirmed that teh collection key and the value in KEY_LOOKUP are the same, but after running this block the number of records in teh collection doubles

CF10, Solr

1) is what i am trying to do possible?

2) what am i doing wrong?

Thanks