This is the Normal Behavior when you create DDT Data types and assign %MW to a BOOL Variables Because %MW is 32 BITs so it will reserve 2 words.
IN DDT variables either we create all variables as BOOL and in this case, we can use %M Or all variables as DINT (32 BIT) and in this case, we can use %MW
IN DDT variables either we create all variables as BOOL and in this case, we can use %M Or all variables as DINT (32 BIT) and in this case, we can use %MW