those values are hardware fixed settings.
you can have a look on the bestech site.
they offer a range of values you can choose by your own when ordering the bms.
After they produced your bms the values also fixed and you can´t change it anymore.
If you want a bms where you can change the values, you can have a look at smart bms.
There is too less information on the bms you linked but i doubt that the bms is balancing form 2.9V till 4.2V.
it´s more the max and min voltage range the bms monitor the cell and cut off in case one cell come out of this.
I guess the bms doesn´t start balancing before 3.9V or even higher.