Can't change % for timed charge from App or cloud dashboard

Now we have the prospect of a few sunny days (southern UK) I've been trying to lower the % charge in the inverter's Settings/ 'timed charge' section of the app. Repeated attempts over days sometimes seem to be 'accepted' but others get a returned error.
I have the GivTCP link set up in Home Assistant and have tried there to make the % change without success. Any ideas, please?
Apologies if this has been answered elsewhere - I did look!
AC3.0 inverter with 8.2 battery.
Cheers, Andy

Fortune7 go to the configuration of GivTCP and ensure that SMARTTARGET is disabled, this can override some settings.

Also, if you're on an Octopus tariff check you don't have any automations set on the Smart Tariff card in the GE portal

Many thanks - I'll try that. Right now I'm migrating my Homeassistant to a different machine but I'll add it to the list of stuff to sort out!

Andy