I have had 5kw solar plus 13.5kw AIO installed with a Gateway in early May. After a couple of days getting used to the app, I can assure you that you have not made a mistake…I am obtaining all my electricity needs, providing some free power to my EV’s and selling 13.5kw (on top of any solar direct export) back to the grid each day using my Intelligent Octopus tariff.
Make sure your application for export tariff is in and being processed - I found Octopus communicated well and the whole process only took two weeks. Until then I used surplus power on my immersion heater (which I have fixed a wifi control to) and my EV’s.
I don’t recall having the problems that you have with exporting rather than serving home demand but I do recall having problems with the quick buttons: the “pause” did not work for me which could be your problem. I think that by playing with the settings I usually achieved my aims but I suspect your problem has arisen because of last weeks update to the Android app: there are several community strings referring to problems following this and I contacted GivEnergy Support about it, who say they “are working on it”. I suggest you email Support and get them to check your settings or otherwise confirm that it is a problem at their end. They will respond within 24 hours.
I use Eco Mode by default and enable Timed Charge Mode to coincide with the 23.30-5.30 cheap tariff with IO. I have also enabled Timed Export to discharge to the grid between 21.15 and 23.30 so that the battery will empty (to 6%) and then recharge overnight at cheap rate. However after the App “upgrade” it appears that enabling Export Mode disables Eco Mode so I have to remember to manually toggle the switch each morning to ensure that the battery serves home demand in the absence of sufficient solar. I expect that this will be resolved in due course but to be honest, it is less than 1kWh/da if I do toggle it late.
I have not had any problems with the grid serving high demand - it always makes up for any shortfall in the battery (ie if demand is over 6kw). If GivEnergy cannot spot an issue in settings I think you may need to get your installer to check the configuration.
Don’t worry about minor flows of 16w…it could be meter inaccuracies, it may be real flow but it is insignificant over the day. Check your Energy Graph and you will see what I mean.