I took a stab at explaining how my pump works so non-diabetic friends and family could understand... it was harder than I thought! click below to read:
http://despitemypancreas.blogspot.com/2013/08/insulin-pump-101-basics.html
This made me realize that the OmniPod is subtracting the IOB from the summary of bolus and correction. In my opinion this is not the recommendable approach. The IOB should just be subtracted from the correction alone. In this case it should just reduce the correction to 0. Thus the correct calculation should be 2.0 - 0 = 2.0. Explanation: you are still digesting the carbs of the previous meal and the IOB is set to work against these carbs being absorbed. Now you have decided to eat more carbs. Of course these carbs need their full coverage too. Just the current BG should be taken out of the equation because it is still fluctuating under the influence of carbs and insulin activity. So there is no correction needed now - or only with unusually high numbers for the postprandial phase. I suppose this behaviour can not be adjusted/corrected in the OmniPod?
To my knowledge, there is no way to change the way it makes these calculations... but I could be wrong!
Although it would have been easy to implement the OmniPod does not offer options for the IOB calculation. With the current calculation the stacking of insulin can lead to injecting less insulin than needed for the carbs of the second meal. This is something to keep in mind I would say. It might turn out as fine for you but as a general settings for all people on the OmniPod I have my doubts.