The percentage reading you can see is a reasonably good estimate, but unfortunately it can reduce in accuracy over time.
Fully charging the battery tends to 'reset' the algorithm but there may be cases when it displays 100% and still has the capacity to absorb more energy.
This is normal and is not a fault in the system.
If you are still concerned there is an error with your battery, please contact your installer or battery manufacturer in the first instance.
If you need any support regarding your credits or hub, please contact us at support@levelise.com