It is confusing, but you only have to reset the 2-stage and 3-stage voltages to their proper values if you have been playing with the single stage voltage.
My reading is that the LKL mode switch has three positions. The LK's has two. (I have an LK and it is easy to operate, but hard to explain in writing.)
The problem with the LKL manual is para 10 says left and right, the same as the LK's. They should have said the middle for the 2-stage mode in its para.
I don't know where you got the idea the PD is of higher quality than the PowerMax. I have had PowerMax converters for ten years and can recommend them. I have not had a PD, but I assume a PD would keep on ticking too.
I much prefer to have manual adjustable voltage than the fixed voltages of the Charge Wizard for my applications, but for LFPs it appears the standard PD with CW would be OK, and there is no real need for their new "LFP" versions (which I take to be a "Sales" idea too as in the OP above.)
It is good there are options out there for all tastes and opinions.