Now he's suddenly decided that he wants to change the arrangements to 50/50, I'm guessing because he anticipates his business making some serious money next year and doesn't want to pay me child support. He's also saying he won't have to work at night anymore, so he wants kids more often, yet he also wants to give me 3 nights a week and one on the weekend, where I have to arrange after school care (at my expense) for the younger child, and the 12 year old will have to come back to my place alone and be by himself for 1.5 hours or more until I collect the other one and get home. While this is not illegal, it doesn't thrill me. On the nights I am a bit late at work the older one will have to go and pick up the younger one from after school care (I can't think of what else to do - I have no family to help). The school is a 5-10 minute walk away but if he locks the keys inside or something goes wrong it would be an issue.
He can actually continue to pick them up every day since he has his own business and can work whatever hours he likes, but is just trying to be difficult and suit himself.
If the kids are enjoying a parenting arrangement and settled in the routine, is he allowed to just change it so that he doesn't have to pay child support?