Some CNC controls has just one option for G04 dwell time the number of seconds the machine will wait, but now you have a rather easy and a bit economical way.
Suppose you are using a reamer or flat drill for boring plus bore-face finish, previously we just guess how much time will it take to finish the face in the bottom, it might be 2 or 3 seconds.
But now just easy give the number of revolution and the G04 dwell will finish when the specified number of revolutions are complete. For a machinist it is the easier way because now he handles it the machine way not like a stop watch.
The code below says that the machine will wait for the next three seconds.
N1 G04 F3
The easier way the code below says that the machine will wait until the spindle revolves round 3 times
N1 G04 S3