PSO: Working Time Rule Issue

Hello,

I am trying to create a WORKING_TIME rule in PSO Standalone (version 6.16) that limits the maximum working time within a specific reference period.

To do this, I have defined the following elements in my XML:

<DsModelling xmlns="http://360Scheduling.com/Schema/DsModelling.xsd">
    <RAM_Rule_Type_Parameter>
        <parameter_id>MaximumTotalWorkingTime</parameter_id>
        <ram_rule_type_id>WORKING_TIME</ram_rule_type_id>
        <ram_data_type_id>TIMESPAN</ram_data_type_id>
        <default_value>PT8H30M</default_value>
    </RAM_Rule_Type_Parameter>

    <RAM_Rule_Type_Parameter>
        <parameter_id>ReferencePeriod</parameter_id>
        <ram_rule_type_id>WORKING_TIME</ram_rule_type_id>
        <ram_data_type_id>TIMESPAN</ram_data_type_id>
        <default_value>PT8H30M</default_value>
    </RAM_Rule_Type_Parameter>

    <RAM_Rule>
        <ram_rule_type_id>WORKING_TIME</ram_rule_type_id>
        <id>1</id>
        <description>Working Time</description>
        <global>false</global>
    </RAM_Rule>

    <RAM_Rule_Collection>
        <id>TEST RULE</id>
    </RAM_Rule_Collection>

    <RAM_Rule_Collection_Rule>
        <rule_collection_id>TEST RULE</rule_collection_id>
        <rule_id>1</rule_id>
        <rule_type_id>WORKING_TIME</rule_type_id>
    </RAM_Rule_Collection_Rule>

    <RAM_Rule_Type_Category>
        <id>ROTA_VALIDATION</id>
    </RAM_Rule_Type_Category>

    <RAM_Rule_Type>
        <id>WORKING_TIME</id>
        <rule_type_category_id>ROTA_VALIDATION</rule_type_category_id>
    </RAM_Rule_Type>

    <RAM_Rule_Parameter>
        <ram_rule_type_id>WORKING_TIME</ram_rule_type_id>
        <ram_rule_id>1</ram_rule_id>
        <parameter_id>MaximumTotalWorkingTime</parameter_id>
        <parameter_value>PT5H</parameter_value>
    </RAM_Rule_Parameter>

    <RAM_Rule_Parameter>
        <ram_rule_type_id>WORKING_TIME</ram_rule_type_id>
        <ram_rule_id>1</ram_rule_id>
        <parameter_id>ReferencePeriod</parameter_id>
        <parameter_value>PT8H30M</parameter_value>
    </RAM_Rule_Parameter>
</DsModelling>

 When importing, I receive the following error message:

When I remove the MaximumTotalWorkingTime parameter (I have also tried MaximumTotalTime), no error message appears, but the rule is not applied either.

Does anyone have any idea what might be causing this?

Thank you!