He means the personal timer, not the instance lockout timer.

Instance lockout timer can be extended if Dalriada keeps popping frequently because people are doing FATEs and resetting it's cooldown faster.

Personal timer can't be extended, you can get lucky and get into a CLL or Dalriada just as your timer is about to expire and you won't get kicked out till you finish it. But otherwise only way to refresh your personal timer is to go out and in again.