Most of this will be obvious to you, however it would be wrong of me to assume what you do and don't know, so let's go for a ride, so that we're in the same page.
Let's take a look at the diagram for Ecosmart TSM (Tidal Swell Mode)
Look at the white portion of the graph labeled "same", the orange is labeled "opposite" and blue is labeled "back". It may not be obvious but humor me let's equate "same" with 'sync', "opposite" with 'anti-sync', and "back" with 'ecosmart back'.
Now, make a mental note how ecosmart back slowly crests and then rescinds for what looks like 75% of the daily schedule.
Ok, now let's look at how "ecosmart back" is set up in mobius:
I randomly dragged child into the schedule and selected ecosmart back.
Now, here's the part most people get confused about with "child mode" That turquoise slider on the right doesn't mean that the pump will peak at 60%, it means it will run at 60% of the parent pump.
I don't know the percentages of your parent pump that is set to Ecosmart TSM (Tidal Swell Mode). But to make the math easy, let's say your parent pump has the slider set at 50%, and your child pump (set to ecosmart back) also has the slider set to 50%. That means the child is only operating at 25%. For the 1st 18 hours of the pumps programming it's only going to speed up and slow down 12.5%. And when you do the math (12/100 = x/12.5) 12.5% is 1.5 white led lights. You're guess is as good as mine if you're going to see that white led move once in the 1st 18h.
If the slider for the child was at 100% then it would work at 100% of the capacity of the parent, which is set to 50%. In other words the child will also cap out at 50%.
I know that this is confusing at the beginning but once you understand how it works, you quickly realize this is the best approach for parent/child relationship.