why is the semantics of `CUSTOM_SQL_EXPR` and `CUSTOM_SQL_STATEMENT` are opposite ? 

Currently for `CUSTOM_SQL_EXPR` return `true`, it would considered as success. while `CUSTOM_SQL_STATEMENT` returning `true` it is considered as failure. 

If really the rules are considered as assertion, shouldn't the  `complex_rule_validation_success_flag` be `true` instead when  `CUSTOM_SQL_STATEMENT` is returning `true` ? 