Maybe an example will help.
Let’s say I have entered my first 1/3 with my short strikes at 1000 (with the market at 1020).
If the market goes to 1060 it has moved past my first addition point and is now at the 2nd addition point. Would I now enter a full position with butterflies at 1020 and 1040? From your reply I think the answer is yes but I want to make sure.