Get Database Items Dynamically in Fast Formula

Team,

We have a Fast Formula as an Extract Rule.

In Fast Formula, we are trying to get database items dynamically from Table Valueset based on the element name passed from Fast Formula.

When we use l_balance_value = UNION_DUES_202_ASG_RUN , Its working.

When we use l_balance_value = TO_NUM((GET_VALUE_SET('ELEMENTS_R9_VS','|=ELEMENT_NAME='''||l_element_name||''''))) - Here "UNION_DUES_202_ASG_RUN" comes from Table Valueset. - Its not working.

Please guide me.