On the left side I have a list of (currently) 3 items. These items have their own list of changes on the right. See screenshot:
This represents "new data --> [position]". The application gets a file that contains the data and directly sends it to a machine. The data is an instruction, and what the previous data is/was doesn't matter for the user. So there is no concept of going up or down or adding/subtracting.
This application is normally minimized, but if someone wants to see what happened they need to be able to understand this without having to read a lot or ask me.