Macro that checks a list, and gives user prompt for action

The things you would like the macro to do seems very feasible, and rather simple to achieve. But the question is, how is the data being compared?

Is the data in "Data" worksheet the 'current state' of the data and in "Table" worksheet are the upcoming updates needed to be done/applied for the list of items?

Edit:
Another question, for Item 5, it has 100 under phase 3 in "Data" worksheet, and has 100 under both phase 3 and 4 in "Table" worksheet. You mentioned it's because half of it is being moved to phase 4? How do you determine that 'half' ?