ShanoMac

Definitely noticed an increase my side too. When we moved onto a Prepaid meter over a year ago, I started tracking my daily unit usage - and it was around 7-8 units for the house per day. The DAY we had our inverter and battery installed, it's gone up by the same +-2.5 units a day. I've set my inverter to only charge the battery at midnight for a few hours, but it's for sure that extra power needed to charge the system. Looking forward to the reduction when panels are in

How many batteries do you have? 1600W on DC equates to +-30 amps (depending on voltage) so I think that still more than okay (if you have two, probably still okay'ish if you only have one). And this correlates with the 'AC Charge Battery Current (A)' setting from your screenshot which is set to 30 amps.
I'm not familiar with LuxPower, just extrapolating my limited knowledge from my SunSynk inverter where grid charging is set to 40A (20A each then per battery for 2 batteries) and this typically uses about +-2000W.
The 'Charge Current Limit (A)' setting of 110A probably relates only to DC charging from PV. When you have PV it will again depend on the number of batteries to set this optimally.

Monitor your AC voltage at changeover. If it dips low it can cause amps drawn on the garage door to increase above 1A. 
 

When running during load shedding / grid a multi-meter should show:
L - N -> +/-230V
L - E -> +/-230V
N - E -> +/-0V
Pretty straight forward using a multi-meter set to AC-Voltage.
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