When I feed my ds sw. potatoes, we have the same result. I think what you experienced is normal. I actually found that it worked great to help him poop. The idea for the waiting period is to give that particular food for 3-4 days to see if there is a reaction. Should you not have one, then you can add that food into the regular feeding schedule. I would be careful to make sure you mix up the veggies by color though due to carotinemia where the lo gets an orangish tinge.
HTH
Lena