When Sasuke decided to go with the sound village.
Well she'll only dual wield them on occasion. Both of them are compatible with the phalanx bits to change into various kinds of rifles. The second is mostly treated as a back-up rifle.
I'm also imagining that instead of having the phalanx bits attatched to the rifle from the start, they are instead attatched to the 4 larger Blue Tears units. The glass strctures are now small energy condensers(like in gundam 00) instead of making up a large part of the structure.
Basically Cecilia goes from SEED Destiny to 00
