It´s no problem to have cells within 0,1 % (3 - 4 mV) after 2 years running the pack without any balancing. But those are gently utilized true original Sanyo 18650 cells, not heavily used Lipo. Battery has simple BMS. Charging usually to 4 V max, seldom 4,1 – 4,15 V.
Voltmeter need to have 0,1 mV resolution if you want to measure real cells voltage. In my opinion, there are probably lot of innacurate measurements leading to wrong conclusions, thanks to non suitable measuring equipment.
By the way, Cellog8 accuracy is also not compliant. Inaccuracy is 8 – 12 mV, moreover Cellog is supplied from some cells, this further increases inaccuracy.