BQ24650: BQ24650 Design guide

Hello TI team,

I have query regarding the MPPT setting in BQ24650. As looking in datasheet it provides two types MPPT setting as per below image. Please refer page no 23 and 27 in datasheet.

Method 1                                                                                               Method2

1. From above which one method is good ?
2. If we will use Method 1 than why is it required to use Q3 MOSFET? Is Q3 control from controller?

Please look it here and suggest further.

Regards

Paresh Panchal