Bazi is diagnosis while Fengshui is prescription
Ancient Chinese Sage said: 一命, 二运, 三风水 (one: Fate, two: Luck and three: Fengshui). Basically it means you must have a good fate or destiny, if that’s failed you better have good luck. However, if you have bad fate and bad luck, then your Fengshui is better be good.
In Chinese Meta-physics, Fate and Luck can be derived from your birth date and time. This is also known as Bazi. Fengshui refers to the place that you stay or work. Although your Bazi chart is fixed, your luck is not. It is influence by the environment as we as Yearly Energy (known as Tai Sui). Everybody knows that there are always ups and downs. There is no such thing as absolute, as in the Yin-Yang theory.
So, to summarized: Bazi = 一命, 二运 (one: Fate, two: Luck). Fengshui = 三风水 (three: Fengshui). As such, from Bazi, we can derive what are the ups and downs that are going to befall you. So Bazi can give you indicators of what’s going to happen. That’s why Bazi is diagnosis. For example, changes in career, relationship, wealth, health etc. It could be good or it could be bad. So, if your Bazi indicated that there is windfall, then if your house Fengshui supports it, then you will get bigger windfall. On the other hand, if your house Fengshui doesn’t support it, you might end up losing it. That’s the prescription part of Fengshui. So, if your house Fengshui does not support or match your Bazi, then you will have bad “prescription”. On the case of Whitney Houston, she wouldn’t have died if she moves out of the house. Her house has bad “prescription” that does not match her Bazi. The same pattern can be seen in Elizabeth Taylor's Bazi and her house.
Therefore, in our Qi Men Dun Jia practice, we use the Qi Men Dun Jia Bazi as basis and use it to match against the house Fengshui to provide diagnosis and well as Fengshui adjustment (proper prescription) using Qi Men Dun Jia Fengshui technique.
In addition, Qi Men Dun Jia Bazi can provide information on the good location/direction for wealth (so that you can go to that location to seek wealth and gain more money), good location/direction for health (to increase your chances of getting well from illness), whether you have the capability to become a boss (if you don't have then can concentrate to work for others).
In short, Qi Men Dun Jia Bazi will provides a map of your life. You have the option to adjust it by using Fengshui or through actions.