I can well understand that for a family, $44.00 per day in tips can seem a bit excessive. I would suggest, however, that you don't totally remove the auto-tips for the kids. Maybe leave one of the children's auto-tip on.
Of course, that is just a suggestion, and you and your wife have to do what you feel is best.
As others have said, the cabin steward does have additional work to do when there are four people sharing a cabin, even if two of them are children. He has to break down the beds (upper berth or sofa bed) and then pull them out and remake them each night. Then, of course, when there are four people sharing a cabin, there is gonna be more of a mess. That's to be expected. So, the cabin steward is gonna have more work to do each day in that cabin.
The waiters too will have more work to do since there will be four of you being served, rather than just two.
So, consider that fact when deciding how much of an auto-tip to leave on.
As I said, I have had friends who've removed the auto-tip maybe for one of the children, leaving it on for the other. I also have one who removed it entirely for the children staying in the group of cabins the extended family had. Generally, they would leave in place two auto-tips per cabin and they had something like six cabins. They felt that was enough, and that's their choice.
Again, tipping is a highly personal matter and you should do whatever you feel is right.