What is the expected time of execution between each wave in a wave group?

I was checking the execution times between each wave within a wave group and I have been able to see that it takes between 4 to 5 seconds. If I consider a wave group of 50 waves, we would be talking about between 200 to 250 seconds (3:20 to 4:10 minutes) adding to the execution time of each wave. Do you know if those 4 or 5 seconds is the expected execution time or is there a way to reduce that time?

Start time: 04:14:18

Finish time: 04:30:14

Execution time: 00:15:46

Around 5:36 minutes if we consider the total time beetween each wave.