Trying to understand the schedules for set up

I have been running the Fixed schedule, as that seemed to be the best for selecting 2 days a week to water as per city restrictions. I let it select the default watering times as per my set-up (shade/sun/nozle type/etc.). It’s tuning for 6 hours each scheduled day, which seems excessive, and my water bill has been high. I am in Central Texas with Bermuda, some sections in the sun, some in the shade, a mix of rotary and drip zones. 12 zones total.

I am looking to change to Flex Daily or Monthly as, per the app, those schedules should lean more towards “Savings.”; However, when I set those schedules up, it says my watering time now doubles, and I have to select at least 4 days a week to water. That seems the opposite of “Savings”. I wish the app was more descriptive of how this all works.

What is the logic here?

Thanks