@Anzazuleg I have 3 and a half hours but I think that in your case 4 hours is fine, especially considering that he is a small child so it is better to be a bit conservative.
Well, talk to the doctor and go down to 3, I did not rectify it, total that if one day it is with 200 to an hour, it sticks all day that high.Let's see if it goes better.