It's the same old story about sleeping. They want the boys to sleep as much as possible to avoid taking care of them. Jen uses the same old "I have so much work to do" excuse again and again. She seemed to find plenty of time during the day to screw around and talk about stupid bolt stories or water filter stories.
Oh wait, she was "working" wasn't she. She had to pretend to be helping Tim in the garage (but just sitting in the Tesla) so she could justify the nanny taking care of Oliver inside the house.
I also think that's why they are pushing for the boys to play together, even though they really aren't. They want to be able to just stick the two of them together so they don't have to interact with them.