TBH, if the set is hurting there are 2 possible causes-
1) It is genuinely hurting, and it is in a difficult place, and best be moved. or
2) It could be a possible set problem.
Have to add to this that it is also day 1 on the pump, so your son may be more aware of it.
If he is only aware of it when being reminded, or when bolusing, I would be temoted to leave for another couple of hours.
If it is hurting all the time, I would change it, sets when they are in the right placve, should be undetectable, and totally pain free.
However, you are talking about a child, and I am speaking from my experiences as an adult.
Also, I would never let settings be at 16. The combo machine is set up to think a lot better than us humans....it takes in to account bolus on board, active time, basals, bolus etc, correction factors etc. Me personally, I would lower that value down to 10 or 12, as this is only your first day, it is really impressive that you have looked at this!"!"!!!!!!!
You willl love the remote on the combo, but there are a lot of things that efffect levels initially.....and on a long term basis too....if you have realised the settings like this already, I am impressed.
Well done, on getting a combo. From an adult view I love it, because it is so discreet. When latched up to my arm, I never think about it, and do everything by remote......it is so discreet and user friendly.