If you want to advance a high frequency emitter by a large time period such as 1 second you should call this command multiple times with a small time value such as 0.02 so that it creates new particles in batches and spreads them out evenly. Calling it once with a large time value of 1 second would create a huge batch of particles all at once and move them together as a blob instead of spreading them out. 

You don't need to call this method for regular particle updates.

TAgkParticleEmitter Methods