It shouldn't. Adding FSD should not constitute an order change. Adding FSD on existing order is also pretty much the only thing you can do yourself, online, without having to call your SA. Removing FSD online updates your pricing. Removing FSD via SA seems to be inconsistent - some SAs help the customer, some SAs screw the customer and update their pricing.doesn't adding/removing FSD change the car price to newer values?
Remember, you can also add FSD after delivery and pay the $10k with a credit card, for people who don't want to finance the cost. So it wouldn't make sense to penalize active existing orders for adding FSD.