Why are the results calculated by different fortune-telling methods different?

Because the person you are looking for is not at the same level.

As far as fortune telling is concerned, you can't learn all kinds of methods. A method takes at least ten years to get started. It takes at least 200 years to learn all kinds of methods. It will take 40 years to reach the age of 20. So it's normal that the result is different. It is not easy to say simple things, but it is possible to say difficult things. There are everyone on the internet now.