On August 16, Tesla will begin charging an additional $1,000 for the "full self-driving" upgrade, CEO Elon Musk announced on Twitter on Tuesday. The option currently costs $6,000. It's the latest in a series of price changes for a package whose main function—"full self-driving"—is still largely aspirational.

The price hike reflects Musk's view that Tesla is less than 18 months away from delivering full self-driving technology to customers and that this capability will drastically increase the value of Tesla vehicles.

"That's approximately date when we expect Enhanced Summon to be in wide release," Musk explained. "It will be magical."

At an April event, Musk predicted that Tesla vehicles would be capable of operating as autonomous taxis by the end of 2020. In a back-of-the-envelope calculation, Musk estimated that a Tesla vehicle could generate as much as $30,000 per year in profits. If that came to pass, it would easily make even the cheapest Model 3 worth more than $100,000.

"If you buy a Tesla today, I believe you are buying an appreciating asset – not a depreciating asset," Musk said in an April podcast episode. If his predictions are correct, the full self-driving package should be worth tens of thousands of dollars by the end of next year—which makes next month's expected hike from $6,000 to $7,000 look quite modest in comparison.

Of course, Musk's predictions may not be correct. In fact, there's a lot of reason to be skeptical. The Tesla CEO has a long history of being overly optimistic about Tesla's progress—especially when it comes to self-driving technology.

Back in 2015, Musk declared that full autonomy was "a much easier problem than people think it is" and predicted it would take about two years. In early 2016, Musk predicted that people would be able to "summon" their cars from thousands of miles away "in ~2 years." In October 2016, Musk predicted that Tesla vehicles would be able to drive coast to coast without human hands on the steering wheel by the end of 2017.

Needless to say, that didn't happen.

Tesla keeps changing full self-driving prices

Tesla first introduced the full self-driving package in October 2016. At launch time, customers had the option to pay $5,000 for the "Enhanced Autopilot" package, which featured lane-keeping and adaptive cruise control. Paying another $3,000 got a customer "full self-driving," a package that didn't initially do anything but could—eventually—transform a Tesla into a fully self-driving car.

Two years later, people who had paid for the package didn't yet have anything to show for it. Tesla yanked the package from its website. Musk explained that the option was "causing too much confusion."

Then in February 2019, Tesla reintroduced the full self-driving package along with a new Autopilot pricing structure. The $5,000 "Enhanced Autopilot" package was gone. A subset of its features got repackaged into a new $3,000 "Autopilot" package. Meanwhile, the cost of the full self-driving package was raised from $3,000 to $5,000. Advanced capabilities like "Navigate on Autopilot" (which guides a Tesla from on-ramp to off-ramp) were part of the new, more expensive full self-driving package.

In a controversial move, Tesla also offered existing customers big discounts on the full self-driving package. Customers who already had Enhanced Autopilot could get the full self-driving package for $2,000. That was a bitter pill for people who had pre-ordered the package previously for $3,000 or more (it had cost more if purchased after the car was delivered), hadn't yet gotten anything for their money, and weren't offered a partial refund.

A couple of weeks later, Elon Musk admitted it had been a mistake to offer the discount. Tesla went back to charging everyone $5,000 for the full self-driving package. Then in April, Musk announced that the price of the full self-driving package would "increase substantially over time." Tesla soon raised the price from $5,000 to $6,000.

Now, just a few months later, Tesla is raising the price again, from $6,000 to $7,000.

"Cost of the Tesla FSD option will increase every few months," Musk wrote. "Those who buy it earlier will see the benefit."