Battery % unstable after firmware update

Recently updated my 9.5kWh battery from 3008 to 3012. Worked perfectly for 10 months from new, but since update the % charge at low levels is unstable. It regularly drifts downward (reserve now increased from 6 to 10%) and upward, but occasionally it crashes to zero which triggers a grid charge up to reserve.
This is bad for the battery, bad for me and must be wrong ??
For information I run the system set for solar charge only and use a simple fixed tariff ( 2 tier tariffs are a rip off in my opinion).

There is now a new firmware 3015. (I've not tried it - 3012 seems to be working fine for me.)

SOC problems seem to have been going on for a long time now :-(
Presumably if you are charging only from solar, your battery rarely reaches 100%? Perhaps that's another thing that's changed recently, in addition to the firmware change. I have heard on here that regularly visiting both extremes of the range of the battery allows the BMS to keep better track of charge status. (Otherwise it tracks energy in and out, and errors will accrue over time.)

2 tier tariffs are working very well for me, but maybe it depends on relative battery size/daily consumption.

gmincca I'm more than happy to be 'ripped off', it's saving me over 50% compared to a standard tariff. I did my sums at 90% cheap rate, 10% standard rate and would have achieved far better than that had it not been for a calibration event.