So the price delta between 300 mile and 500 mile is $30,000.
2 kWhr per mile means the 300 mile is a 600 kWhr battery and the 500 mile is 1000 kWhr.
400 kWhr's for $30k means they are expecting $75 per kWhr battery costs. Last year they said it was under $190 per kWhr.
I am very skeptical they can meet that target, $75 would be pretty revolutionary in such a short time.