Firebird MVCC engine detect the "Update Conflict" ( Lost update) under concurrent transactions. This is very nice architecture of Firebird. But, many benchmarks of RDBMS assume existance "Lost update" like pgbench or DBT1.
I propose New configuretion parameter to firebird.conf called "AutoDetectUpdateConflict" default is TRUE. But, to set this parameter to FALSE then Firebird will not deletect update conflict like MySQL.
Auto detection "Update Conflict" is an advantage of Firebird MVCC engine, but this is an disadvantage of many benchmarks for other RDBMSs.