Battery percentages

[Brushhand1]

Hi guys
Just wanted your thoughts we have a 5kwh ac inverter and 10.4 kWh storage system connected 4 months ago to our 7yr old solar array. Over the last few weeks we charge overnight because solar is poor this time of year. However we have conflicting data on the fox app the fox pc information and the in house smart meter display. All saying different amounts of charge being achieved overnight ranging from 6kwh ..to 8kwh never close to the expected 9 kWh which it should be with setting at 100% capacity.
On further inspection this has been the case from the beginning.
How can I get the correct information is the only way from 10% soc force charging the battery’s with no other load from the house then reading the actual smart meter itself to see if we have achieved anywhere near that.
Many thanks
Brushhand1