xslt calculating insurance writeoff not working - xslt

Question

I am trying to calculate the contractual write off for medical insurance but the calculation doesn't seem to be working. For example, I need to take the value of the charge attribute on the <charge> tag and subtract the value of the amount attribute on the <adjustment> tag but only when the group and code attributes on the <adjustment> tag are: group ='CO' and code = '45' or '385'
I was able to get everything but the calculations working. I've tried looking at several answers on this forum but am obviously missing something. Any help would be appreciated.
Here is my XML (simplified):
<result check_number="05173408" ...>
<claim ... total_charge="720" total_paid="43">
<charge charge="200">
<adjustment amount="125" code="45" group="CO" />
<adjustment amount="35" code="385" group="CO" />
<adjustment amount="20" code="3" group="PR" />
</charge>
<charge charge="70">
<adjustment amount="70" code="204" group="PR" />
</charge>
<charge charge="300">
<adjustment amount="273" code="45" group="CO" />
<adjustment amount="15" code="3" group="PR" />
</charge>
<charge charge="150">
<adjustment amount="139" code="45" group="CO" />
</charge>
</claim>
</result>
Here is my xslt to date:
<?xml version="1.0" encoding="UTF-8" ?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" exclude-result-prefixes="xsl">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes" />
<xsl:template match="/">
<!-- maps to the beginning result tag -->
<xsl:for-each select="/result/claim/charge">
<!-- amount allowed by the insurance for line item -->
<COL>
<DATA>
<xsl:apply-templates select="adjustment" mode="calcAdjTotal" >
</xsl:apply-templates>
</DATA>
</COL>
</xsl:for-each>
<!-- Template created to test Parfait's suggestion -->
<xsl:template match="adjustment" mode="calcAdjTotal" >
<xsl:variable name="condition" select="adjustment[#group='CO' and (#code='45' or #code='385')]"></xsl:variable>
<xsl:value-of select="../#charge - sum($condition/#amount)" />
</xsl:if>
</xsl:template>
</xsl:template>
</xsl:stylesheet>
Here is my output: (updated output)
<COL>
</DATA>
</COL>
<COL>
</DATA>
</COL>
<COL>
</DATA>
</COL>
<COL>
</DATA>
</COL>
Here's what I want to get:
<COL>
<DATA>
40
</DATA>
</COL>
<COL>
<DATA>
</DATA>
</COL>
<COL>
<DATA>
27
</DATA>
</COL>
<COL>
<DATA>
11
</DATA>
</COL>
The format will then be used to import data into Filemaker.

Answer 1

Consider wrapping your conditional equation in an <xsl:if>. Additionally, you can do so with a variable storing the conditional value to avoid repetition:
<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output version="1.0" encoding="UTF-8" indent="yes" />
<xsl:strip-space elements="*"/>
<xsl:template match="/">
<ROOT>
<xsl:apply-templates select="*"/>
</ROOT>
</xsl:template>
<xsl:template match="charge">
<xsl:variable name="condition" select="adjustment[(#code='45' or #code='385') and #group='CO']"/>
<COL>
<DATA>
<xsl:if test="$condition">
<xsl:value-of select="#charge - sum($condition/#amount)"/>
</xsl:if>
</DATA>
</COL>
</xsl:template>
</xsl:transform>

Answer 2

I am guessing (!) you want something like:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/result">
<RESULT>
<xsl:for-each select="claim/charge">
<ROW>
<COL>
<DATA>
<xsl:value-of select="#charge - sum(adjustment[#group='CO' and (#code='45' or #code='385')]/#amount)" />
</DATA>
</COL>
</ROW>
</xsl:for-each>
</RESULT>
</xsl:template>
</xsl:stylesheet>
Applied to your input example, the result will be:
<?xml version="1.0" encoding="UTF-8"?>
<RESULT>
<ROW>
<COL>
<DATA>40</DATA>
</COL>
</ROW>
<ROW>
<COL>
<DATA>70</DATA>
</COL>
</ROW>
<ROW>
<COL>
<DATA>27</DATA>
</COL>
</ROW>
<ROW>
<COL>
<DATA>11</DATA>
</COL>
</ROW>
</RESULT>
This assumes you want to create a record (with one field) for each charge.
Note that this is not valid FileMaker XML syntax.
-- edited in response to clarifications in comments: --
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/result">
<RESULT>
<xsl:for-each select="claim/charge[adjustment[not(#group='PR')]]">
<ROW>
<COL>
<DATA>
<xsl:value-of select="#charge - sum(adjustment[not(#group='PR')]/#amount)" />
</DATA>
</COL>
</ROW>
</xsl:for-each>
</RESULT>
</xsl:template>
</xsl:stylesheet>
Result
<?xml version="1.0" encoding="UTF-8"?>
<RESULT>
<ROW>
<COL>
<DATA>40</DATA>
</COL>
</ROW>
<ROW>
<COL>
<DATA>27</DATA>
</COL>
</ROW>
<ROW>
<COL>
<DATA>11</DATA>
</COL>
</ROW>
</RESULT>