When I switched DD from s26 to Nan, the exact same thing happened. It was like she was back on breastmilk.

It will most likely settle down a bit, but there's nothing wrong.
Thats exactly what its like!! Like he is on breastmilk. Is your DD still on the nan?

I just spoke to my CHN and she said that nan is less in casein (sp) and she thinks DS might be a bit casein sensitive (how that works when he was ok on s26 gold but not s26 AR i dont know) and that pooping like a bf baby when hes on formula is a good thing and normal and hes all good.

Thanks for your reply, its much appreciated