settings 1 & 2 allow you to switch between displays. By that I mean, 1 & 2 both display exactly the same MFA data, but give you the option of keeping one set of trip information, while resetting and using the other.
For example, setting 1 you can use for long term trip info, say what you do in a period of time, while you can switch and use setting 2 for one off trip data.
Hope that makes sense.