APEX

When calling APEX_IR.ADD_FILTER against an IR column, is there a reason it only uses ‘EQ’ operator in stead of any other operator?

APEX_IR.ADD_FILTER (
            p_page_id   =>    p_page_id,
            p_region_id =>    v_region_id,
            p_report_column => 'A500_VOUCHR_NR',
            p_filter_value  => APEX_UTIL.GET_SESSION_STATE('P5_VOUCHER_NBR'), 
            p_operator_abbr => 'C', 
            p_report_id     => NULL );

This code always revert back to EQUALS TO ('EQ') when the filter runs

Is there an override in the column properties?