1. ORDER NO:
REORG PLUS for Db2 ignores option KEEPDICTIONARY (whether if YES or NO is specified with KEEPDICTIONARY), always build dictionaries for all partitions (existing and newly added).
Further explanation:
•    If there are existing partitions and no newly added partitions, dictionaries will be built only for those existing partitions.
•    If there are both existing partitions and added new partitions (during REORG), dictionaries will be built for existing partitions and newly added partitions.

2. ORDER YES
•    When ORDER YES and KEEPDICTIONARY NO options are used in REORG, and If there are only existing partitions and no newly added partitions, then REORG PLUS for DB2 will build the dictionaries for those partitions. 
•    When ORDER YES and KEEPDICTIONARY YES options are used in REORG, and If there are only existing partitions and no newly added partitions, REORG PLUS for Db2 will keep the existing dictionary for those existing partitions. If there are are no dictionaries for those existing partitions, then REORG Plus for Db2 will build dictionaries for those existing partitions
•    When ORDER YES and KEEPDICTIONARY YES or when ORDER YES and KEEPDICTIONARY NO options are used in REORG, If during REORG, REORG PLUS for Db2 adds new partitions, dictionary will be copied from the previous existing partition regardless of KEEPDICTIONARY value.