Dennis Quaid and his ex-wife, Kimberly, are switching up how they take care of their kids ... and now it's a more even split.
According to new legal docs, obtained by TMZ, Dennis and Kimberly agreed to a 2 weeks on, 2 weeks off schedule for child custody ... with each parent getting their twins for 2 weeks at a time and then swapping.
In the docs, the actor's ex says if Dennis can't take care of the twins for some reason, she will look after them and Dennis will pay her $225 per child for every day he misses.
As we first reported ... the 2018 divorce agreement with Kimberly called for her to get the lion's share of physical custody -- 75 percent.
The twins are 14 and will be starting high school in the fall, but will be going to different schools, so Dennis and Kimberly hammered out a plan to get the kids where they need to go.
The docs say Dennis will pay for a nanny to take the kids to school when Kimberly has the kids, and if the nanny is unavailable on any given day, Dennis is responsible for hiring another caretaker to drive the kids to school and foot the bill.
The twins were born at Cedars-Sinai in 2007 but faced a serious medical emergency. The nurses at the hospital accidentally gave them 10,000 units of a drug when they were supposed to receive a dose of 10 units. They survived the overdose and the Quaids received a $750,000 settlement from the hospital.