Child care subsidy + 2nd child

Number 2 is due around Christmas this year, so just planning ahead here.
I’ll probably stop work at the end of November. Currently number 1 is in 4 days a week at child care. My understanding is that I’ll need to drop her down to 3 days (the 72 hours per fortnight guaranteed days thing) once I stop working, to ensure I don’t incur out of pocket costs. Anyone who is very across CCS who can confirm? I was born here and English is my primary language and the Centrelink page really makes me question my comprehension abilities.
Thank you!