The company is likely making the change for two reasons: First, to save money. With a single dashboard design, the company’s software interface engineers won’t have to design two versions of the cars’ controls, one vertical and one horizontal, as they do now. Second, the move may be meant to prepare the cars’ interiors for autonomous driving. Along with the new floating-screen dashboard, the documents show Tesla’s more expensive models are supposed to get upgraded interior materials and seats. Critics have long remarked that the cars’ interior materials are unfit for $80,000 to $130,000 luxury cars. The new interior will also incorporate a wireless phone charger and offer improved interior storage, addressing another long-time complaint.