Board Thread:Event Official Threads/@comment-25730832-20161115130504/@comment-27669891-20161124020051

Saiuns give 1.3x  bonus to the Interception/Anti-Bomber power of the Interceptors, having 2 LBAS consists of 3 rank 7 Interceptors & rank 7 Saiun will guarantee AS+ condition and prevent any damage to the base.

Any lower ranks of Interceptors will not have the AS+ condition, even though the base will not be damage, but that's not the debuff requirement.