No. not anymore.
I used to but then sometime not have place for baby - unless hold empty place and incurring bigger loss. Or Mom switch job and need new hours and I lose both anyway.
I not know many other service provider who incur 40% loss drop FT to 3 days for full year on promise of maybe another child. It same as having FT place sit empty for 3 full month of year. It not often it take 3 month find another good fit family who need FT care so replacing make more sense and smaller loss.
Now, they either stay FT if they hoping for place for baby or they leave and take chance if I have place when need.
I would not give any FT client 3 month off, no pay, assured place on return, so allow drop to 3 days for whole year is same deal. This almost same as having all teacher child and no fee or care for Summer, March Break and Christmas.