I came across this error last night, while making an attempt to combat the tunneling issue, which I admit I have to do more reading on and that I might be going about this the totally wrong way. I’m only a month into pumping after all.
My CF is 1:5 and my i:C is 1:12. I was eating out and allowing myself 71.5g, having looked up the restaurant’s nutrition info. My BG was at 120 (which is my low end for correcting). If I put those numbers into the calculator, I would have had a bolus of 15.65u. So I wanted to split it up into dosages closer to 5u each.
I first put in 20g and my 120 BG to get a 5.65u bolus. I waited until that was delivered and started a second calculation with 25g and 120 BG, and got 5u. It was then that I realized it was already counting the previous bolus as IOB and reducing my calculation accordingly - anti-stacking and all that. But if had done my 3rd segment this way (26.5g and 120 BG), it would have reduced it again and i would have taken a far less units than I wanted/needed.
Moral of the story, you have to use the calculator with everything to calculate your bolus, but then enter each manually to actually get that dose.