I saw this and I was fairly sure of it .I have been dealing with all kinds of LFP cells for over 10 years, very large cells and packs, anything you can imagine I have seen in real life. Never seen a need for active balancing. Blue elephant gun must be working as I can't see any blue elephants anywhere.
Sorry for sarcasm, this subject is a pet peeve of mine. People pay way too much attention to balancing, making it into some mysterious thing. It's just not there. Not even with old cells or very big ones.
One thing is true, if your cell has enough self discharge to require a lot of ongoing balancing, you need a solution. And the best solution by far is to replace the cell, not to spend futile efforts in balancing it. Don't throw good money after the bad.
All cells get out of balance . Their individual capacities are always changing . If I charge a 12V battery with say 14 volts current flows and the same current flows through each and every cell. If the imbalance is bad one cell can be at 50% while another is topping out at 3,5v going on 3,65v (100%) before the BMS trips and cuts amps off.
Conversely on the discharge that cell will be 2.5V when the good one is 3.3V. Does not matter the amphours ,what matters is the capacity . The self discharge is not the problem either its the reduction in capacity which is a real factor.
With an active cell balancer attached as well they will hold the cells within 100 millivolts and warn you early this is happening..