XSLT - parse date and time - excel

Question

I am attempting to set the Type attribute of a cell in Excel via XSL. It should look at report/sheet/definition/column and see if there's a type attribute. If yes, it should set the Cell Type to that type and format it in full time (or datetime) manner.
My xml data:
<report>
<sheet>
<definition>
<columns>
<column name="Code" footerText="ISO Code" width="80" />
<column name="Time" footerText="Time" format="DateTime" width="58" type="DateTime" />
<column name="Country" footerText="Country" width="100" />
<column name="SomeNumber" footerText="Country" width="100" type="Number"/>
</columns>
</definition>
<data>
<table>
<row>
<column value="2020-04-02" key="DATE" />
</row>
<row>
<column value="123" />
<column value="10:30" />
<column value="Belarus" />
<column value="0" />
</row>
<row>
<column value="321" />
<column value="12:00" />
<column value="Austria" />
<column value="0" />
</row>
<row>
<column value="2020-04-03" key="DATE" />
</row>
<row>
<column value="456" />
<column value="08:00" />
<column value="USA" />
<column value="24" />
</row>
</table>
</data>
</sheet>
</report>
I have tried printing out $type and $index in the cell and they truly print out properly, but when I try to take the value of $type and use for <xsl:attribute name="ss:Type">, Excel provides me with an error saying it had problems during the load. After checking out the logs, it turns out that it can't parse values like 12:00 into a Time (or shall I say DateTime?). I have two questions:
Is that expected behavior that it can't parse timespan values into DateTime?
Is it normal behavior that it can't parse 2020-01-01 as DateTime as well?
<xsl:for-each select="data/table/row">
<ss:Row>
<xsl:variable name="set" select="column" />
<xsl:variable name="count" select="count($set)"/>
<xsl:for-each select="column">
<ss:Cell>
<xsl:variable name="index" select="position()"/>
<xsl:variable name="type" select="../../../definition/columns/column[$index]/#type"/>
<xsl:attribute name="ss:MergeAcross">
<xsl:choose>
<xsl:when test="$count>1">
<xsl:value-of select="0"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$mergeAcrossHeader"/>
</xsl:otherwise>
</xsl:choose>
</xsl:attribute>
<ss:Data>
<xsl:attribute name="ss:Type">
<xsl:choose>
<xsl:when test="$type!=''">
<xsl:value-of select="$type" />
</xsl:when>
<xsl:otherwise>
<xsl:text>String</xsl:text>
</xsl:otherwise>
</xsl:choose>
</xsl:attribute>
<xsl:value-of select="#value" />
</ss:Data>
</ss:Cell>
</xsl:for-each>
</ss:Row>
</xsl:for-each>