COC Question or ROI for a rehab project

[Mario Morales]

I have a 3 unit property, 2 units were rehabbed last year and are rented out. The 3rd unit will be rehabbed this year. If I am putting in X amount of dollars and expect Y amount of Dollars, is this a scenario where I need to do CoC or ROI. If so, Do I divide the NOI of the rehabbed unit by a 1/3 of the expenses for the building? How do you measure or quantify your efforts, or do you when its only 1 unit in a property of many units.