The GF is built in Phases. If we assume that Phase 1 has output of 15GWh and is scaled up within quarter or two, they will be at scale production after the ramp-up. Also, let's not forget that 30% is just economies of scale projections. There will be new chemistry with improved energy density, new form factor with optimized sizing, new pack architecture with improved cooling and cell interconnections... I do not see cost of battery packs leaving GF to be higher than current cost. This is one of the reasons I did my rough calculation based on current cost.
Let's also not forget, that at $250/kWh price that Elon tweeted shortly after TE introduction, he was projecting slight profit out of the gate, IMPROVING with the shift of production to the GF (in response to the Andrea James question during the ER Call following TE introduction).
So in summary, we have enough information to conclude that my rough calculation based on current pack pricing is CONSERVATIVE.
I commend you for the tenacity to dive into the details, but I think that we just do not have enough information to essentially use this detailed approach to *disprove* guidance that was given by Elon and JB.