Not getting the same capacity from the battery as from the cells

[cajocars]

I have been using my EVE LF280K from Fogstar UK for almost a year; I tested 4 or 5 of them when new using a Zketech-EBC40L and they were all around 278-280Ah (charging to 3.65V with 14A cut off and discharging at 40A up to 2.5V).
I have been using them with a Seplos BMS, I normally charge them up to 3.5V and use an active balancer to keep them balanced.
I've done a capacity test of the entire battery by setting the low voltage protection to 2.5V (normally I would set this to 2.9V); when the first cell hits 2.5V during discharge, the voltage delta is around 0.2-0.3 V and the SoC is still around 8%. This means I'm getting only getting 258Ah of the 280Ah, and that's discharging at maximum 65A (0.2C), but with an avarage of 10A; I think the capacity EVE quotes is discharging at 0.5C from 3.65V to 2.5V.
Would it make a difference if I charged the cells to 3.65V instead of 3.5V? They are normally fully absorbed even at 3.5V: the current drops under 1A within 30 minutes.

 

[Brucey]

When assembled in a pack you are going to be limited by the "worst" performing cells, versus when testing individual cells where there's no other factors to consider. The individual cell tests would be the best case scenario.

 

[cajocars]

When assembled in a pack you are going to be limited by the "worst" performing cells, versus when testing individual cells where there's no other factors to consider. The individual cell tests would be the best case scenario.

Ok, but it’s very unlikely that particular cell has 10% less capacity than the ones I’ve tested

 

[Brucey]

Well it took Eve three attempts to "fix" those LF280K cells (the latest V3 having the octagonal terminals). So maybe that's what you are seeing?