While what you ask is correct, it doesn't seem to me that you have the concept down. You can bank every year up to the amount of current use year points, there are deadlines though. In your scenario, you would use 150 of the 02 points and bank 50 giving you 250 in 03 (50 banked). You'd then use 150 in 03 (100 current and 50 banked) and bank 100 to 04. In 04 you'd use 100 banked and 50 current and then bank 150 points to 05. In 05 you'd use all 150 banked and bank all 200 points to 06 having 400 (200 banked form 05 plus 200 current). That's where it's stop as for 06, if you only used 150 points, you'd lose 50 of the banked points. Many of us use this concept every day in one way or another both from a banking and a borrowing stand point.
The banking deadlines are important and you should learn them. One thing to remember is the deadlines and the TOTAL percent of points that matter now how many times you bank. So you could bank 100 points 9 months out and another 100 (in your scenario) before the 100% window of 6 months. This is where it gets tricky as it's based on your total points, not how many you have at the time. So if you bank half your points in the 100% window, once the 50% window opens, you can bank no more points even if you will lose them. There is the once in a lifetime double secret banking exception to fall bank on, if you know the handshake and the password.