Rank 1 takes 20 points
Rank 2 takes 40 points (from Rank 1) – total used is now 60
Rank 3 takes 60 points (from Rank 2) – total used is now 120
Rank 4 takes 80 points (from Rank 3) – total used is now 200
Rank 5 takes 100 points (from Rank 4) – total used is now 300
The tool tip itself will adjust the numbers as you progress. So if you have 0 points spent the Rank 5 will display a tool tip of 300. If you are already Rank 3, the tool tip on Rank 5 will only display what is left to reach that rank. In this case, if you are Rank 3 already, the Rank 5 tool tip would display that you require 180 more points to complete.
To comment on your reference to the “red” numbers. The color changes based on if you have enough supply to upgrade to that rank. If you have the skill points to reach a rank/level then the numbers are white…if you don’t have enough yet the numbers are red.