HA Energy Dashboard Charge kWh reliable?

[martindell]

I have 7 x HV2600 batteries, just charging overnight - no solar. Each has a nominal 2.56kWh capacity
In theory, that's 17.92kWh of battery capacity - a useable 16.1kWh assuming a min SOC of 10%.

On days when the battery discharges to 10%, Home Assistant shows a subsequent charge to 100% of no more than 13kWh
I don't understand why the battery isn't drawing a charge nearer 16kWh.
I understand there'll be some round-trip losses - but not enough to account for a 3-ish kWh difference.

Am I missing something? Are my assumptions incorrect? Does anyone else have a similar installation with different Home Assistant charge numbers?

I've raised this with FoxESS support but wanted to check in here too.

Thanks in advance if anyone can shed some light on this