Same thing I came up with... different path perhaps.
ie...total production was 2374kwh... of which you used directly only 2374-1606 exported not used by you at the time = 768kwh out of the 2374kwh produced.
So you used 768kwh of your own electrons, but had to then import some 2045kwh from the man... making total usage by you 768+2045=2813kwh
That makes total usage............2813kwh
and total produced...................2374kwh
And so I get the same thing with (2374/2813)x 100 = 84%... so 84% of your electrical needs came from home grown electrons, while 16% was imported from the powers that be.
Interesting that most of your generated power was exported ( 1606kwh as against 768kwh used at the time of production )...... grid makes a good battery
EDIT: It is interesting that it will depend on the billing system, as to whether you need to reschedule the house power usage profile. If you get net metering, and net billing then who cares, but if you get charged at an import rate that is materially different to the export rate, then it may not look too pleasant.
Over in Aust, some providers do net billing ( Flinders Island is one
, but some give you only 5-8 cents/kwh for your export, and charge you up to 25c/kwh for your imported power. In this latter case, you need to get the hot water running during the day only, and any other loads you can schedule in the daylight hours.... particularly at peak solar times.
Tom needs to be on net billing, as his usage does not mirror his production timing.