On the DTG5000+ what is the difference between short and long delay?

On the DTG5000+ what is the difference between short and long delay?

For each of the Delay and Pulse Width, the variable range supported by the DTG 5000 Series hardware is a maximum of 5ns. (short delay) This also allows for a minimum delay of 200ps. For more amounts of Delay and Pulse Width a software mode is used. (Long Delay) See the User manual Vol 2 for more information.