Digging a bit in what DelayUntilToNextTick: it registers the function to be executed next frame and removes it after its been called. So by using delay in a frame by frame basis you are removing and adding a new reference every frame.
Pls someone correct me if im wrong: Tick works the same way, BUT the actor is already registered and simply gets called every frame. So for your tests it might be faster to just use Tick and enable/disable when needed.