I gotta tell you that's a little paranoid. I got the 50% rebate and never heard a peep from Austin Energy. Can you seriously imagine a scenario where they would swap it out? Realistically, how much would that cost the city to do so? I'd call and ask the purpose of that before just dismissing $850. I'd imagine when they created the program more than 6 years ago, the EVSEs were much more wild west back then, so they had to be careful.
My Leviton cost $800 + $350 install at the time 5 years ago (for only 3.6 KWh), I cannot wait for the City to come get the old L2 charger I had put in for anything they can imagine to put in now.
I'll be filing for a second rebate should Tesla ever send me a black signature EVSE. I asked the city rather than speculate. Second car = second rebate for charger & installation.