Deactivating defensive weapons without losing a level? (Kebir Blue)

A sufficient defensive index is one of the conditions to reach game level 3. But, once this level is reached, is it possible to deactivate the defensive weapons without falling back to level 1?
Thanks.

The only other way possible I can think of is to raise your war level first.

just did it, didn't do much special
try adding bases n intercept wings
then click deactivate all

Yep, once your defensive index falls below the requirement for game level 3 you will fall to game level 2. But yes, if you raise your WAR level, then you will go back to game lvl3 and so on.