I imagine it will be similar to past tax rebate incentives. I really have no idea, but I can guess.
If they make the qualifications too complex it's going to create a lot of extra work. If they still have funding, they keep the full amount open. Waning coffers, they begin to reign it in. The best middle ground is to cut it in half at some point based on battery origin. That way they didn't completely erase it. That's a calculated political move that tries to make it work for everyone instead of placing undue burden on EV makers who didn't make the deadline and had customers who were depending on it although stll at a loss. The deal may have already been cut and they are just delaying the announcement. Keep the full amount throughout 2023 and everyone is happy.
The idea was to incentivize US produced EVs, although Hyundai has argued for the rebate with little or no basis. High end is priced outside of rebate ceilings...so that only leaves Tesla and maybe a few other players like the Chevy Bolt. Personally I think a lot of this is going to depend on how much the government want's to incentivize Tesla in particular since they are really the main player here. Past relations have been shoddy at best between Tesla and Uncle Sam, with US leaning more towards GM support publicly. They seem to be better bedfellows, even though Tesla has them beat by a mile.
Hopefully opening up the SC network was seen as a token of goodwill by the GM leaning administration who will continue to support rebates for those buying Tesla.
There. Did that answer your question?