If Tesla is offering a goodwill buyback, they can offer whatever terms they want to if you're willing to accept them. If the value seems fair given your use and it's an amicable buyback that doesn't leave you black listed, then it might be worth it. In NC, the lemon law clearly states the buyback is purchase price minus fair use spelled out as 'Purchase Price - ((Number of miles driven by the consumer * Purchase Price) /120,000)'. You should obviously compare your legal options against what's being offered via goodwill. I don't personally think Tesla has a leg to stand on deducting the tax credit from your refund. It's a credit against your tax liability, not a manufacturer's rebate. If for whatever reason your tax burden didn't allow you to claim the credit are they going to ask for your tax return as proof? While I'm definitely not a tax professional, I don't see anything that fails if sniff test on claiming the credit for yourself. You purchased the car and for reasons out of your control it's being purchased back without even having the official stigma of being a lemon. Unless they're making you a really sweet buyback deal it may be you who's providing the goodwill by letting them take your tax credit off the refund.