If the kids live with you then you are by definition the custodial parent and can claim child care expenses for both kids. You put both kids on your return but say someone else is claiming one of them and you gave that person a signed 8332 allowing the other parent to claim that child.
Our confused seems to be the definition of custody. The IRS only looks at nights with a parent to determine the custodial parent regardless of the amount of split custody in the divorce agreement.
