Btw, this is quite an interesting question, because I did not have the answer 9 months ago: we were accustomed to making +/-10% changes. But, over the past 6 months, we have started using finer adjustments. In fact, there are times when we end up being in between two 5% increments: one is a bit too high while the other one is a bit too low. In that case, we need to use sugar or insulin, but not very frequently: it may take 4 hours or more before we need a correction.
Still, in that case it would be nice to have a finer adjustment than we do! The Tandem pump has that ability, but the Omnipod doesn’t.
Another interesting question is when to use 5 vs 10% adjustment. When we make a decision to adjust, we look at the slope of the up or down curve. When it is severe, and when the corrections are tightly following each other, we use 10 rather than 5. But that is a qualitative judgment, one that is hard to explain or justify 