The start time for the Security Center Battle is decided automatically by the system after reviewing the preferred times submitted by all participating Alliances.

Because of this, the time you select is treated as a preferred time, not a guaranteed start time.

The actual battle start time is chosen at random from the times selected by all Alliances.

Example:

If several Alliances select 19:00 UTC more than any other time, that time will have the highest chance of being selected as the actual start time.