Inconsistent irrigation values with drip irrigation

I have drip irrigation set up for my vegetable garden. I have a flex daily schedule set up for its zone and the zone type is set to garden with emitters as the spray heads.

I’ve had the zone set to run 45 minutes, which translates to an irrigation amount of 0.24" in the soil moisture table.

I’ve noticed that the soil moisture balance drops well below 50%, often close to or equal to zero, unless there’s also been rain adding to the irrigation amounts.

This morning I changed the duration from 45 minutes to 1 hour run time. Strangely, yesterday morning’s irrigation amount changed from 0.24" to 0.18" (makes no sense). Additionally, the planned irrigation amounts for the next two mornings were unchanged, both showing 0.24", regardless of duration, as did the amount from four days ago.

I can’t understand why the irrigation amount seems limited to 0.24", regardless of duration, especially as that amount regularly leaves the moisture balance below 50% (my allowed depletion). If the soil isn’t saturated shouldn’t the irrigation amount increase with duration?