If he registered all the extensions and still in negotiation with you, the game is still on.
Stick with your price if I were you.
"Do I stick with my price or should or come down since it's a typo that I may not be able to sell easily elsewhere?"
It depends on your acquisition cost. If it's low and you feel that your options to resell elsewhere are limited, take the money (or make a middle range counter-offer) and invest it elsewhere.
park it, if you haven't already.
so you'll know if there's convertible traffic.
imo...