Frame timing is half of what is expected

I’m writing a script that puts a stimulus on for 1 second. I use the Actor.Tick() function to do this, where I simply turn on the stimulus for 60 ticks. My refresh rate is 60fps, so this stimulus should be on for 1s. It is, however, only on for 0.5s. Any reason why this is happening? Is this because the Tick function isn’t being called every frame?

Thanks,
HSM