Вставка множества записей через VALUES меняет автоинкремент
mysql> SELECT AUTO_INCREMENT FROM information_schema.tables where table_schema = DATABASE() and table_name = 'test3';
+----------------+
| AUTO_INCREMENT |
+----------------+
| 16 |
+----------------+
1 row in set (0.00 sec)
mysql> insert ignore into test3(name) VALUES ('xxx'),('aaa'),('fff');
Query OK, 0 rows affected (0.00 sec)
Records: 3 Duplicates: 3 Warnings: 0
mysql> SELECT AUTO_INCREMENT FROM information_schema.tables where table_schema = DATABASE() and table_name = 'test3';
+----------------+
| AUTO_INCREMENT |
+----------------+
| 19 |
+----------------+