Hi Onno,
Alf is out for holidays untill middle of October. Then he surely will give his statement to your request.
Your idea about plotting individual basalrates instead of the total sum to check out if the basalrates ar correct won't work!
The only way to check out the correctness of a basalrate is to do a basalrate-testing. This is a period of time, in which no other circumstance which can increase/decrease the bg-level is working. I can describe such a testing for adults, but not sure for children (especially such young ones). In diabetic diseases children are definitely not little adults, because they have their own physiology. And my skills of pedriatic diabetes are not good enough to describe such a testing for children. I suggest you ask your diabetes-team how this testing should be for Annika.
On a normal day she plays, eats, runs and so on, so you never can be sure, why a bg-level has in-/decreased.