I thought (stand to be corrected on this) that the combo pump had target ranges that act for two differing reasons...
1) It takes the lower target level and the upper target level and will try to return you to the middle point of these ranges...mine set at 5.5 lower and 7.5 upper....so it tries to get me back to 6.5.....
2) My targets are set at this so that on the reports, it gives me ...above, within, below and hypo...so with me...anything above 7.5 will be too high, within will be 5.5-7.5, below will be 4-5.5 and hypo anything under 4.
This enables myself a target to aim for....normal peoples (can I say that) do not have a steady, steady reading of bgs...so mine are set to get me to try and aim between a normal persons range...
If I had my combo set at lower target 6.5 and upper target of 6.5 the combo pump will show everything over 6.5 as too high, and everything from 4 to 6.5 as being too low....and reports will not be of much value if you use them...as it will be rare to hit an exact value of 6.5....
It also shows under the reports when worst times are i.e. premeal, post meal, other etc...and this helps me too..
To get your targets to within range you have to have your carb ratio's and correction bolus, and all the background info right...if this is, then I understood that the pump tries to get you back to the middle of the lower target and upper target range....
Hope this makes sense, I only think this is how it works, but it is how I use my combo pump....