Tesla said it expects to sell between 50,000 and 55,000 Model S sedans and Model X SUVs this year, down from a previous target of 55,000. http://finance.yahoo.com/news/teslas-loss-triples-2q-lowers-211431170.html
That's not a reduce delivery forecast for the X; it's a possible reduced forecast for all cars. There was no mix given (in the letter anyway) of which cars might be in the possible shortfall.
The most important line was "Looking ahead to next year, we are highly confident of a steady state of production and demand of 1,600-1,800 vehicles per week combined for Model S and Model X." If Tesla can even meet 800 per week in Q4, and half of those are Model X cars, then Tesla could deliver 4,800 Model X units before the end of the current year (plus whatever token amount is produced in Q3).
Tesla is already producing more cars than that. The shareholder letter indicates a ramp-up to 800 Xs per week in late Q4.
Elon just said they're planning of having a factory capacity of up to 1000 Models S and X for 2000 total (next year). He said actual production numbers will fluctuate and depend on many factors.
As you noted, he said that capacity does NOT equal production, and that while full capacity can be reached from time to time, repairs and part shortages can result in significant drops in production, hence the 2016 projections of 1,600-1,800 average per week. Last I checked, the factory output was zero last week ;-) Still seems like wishful thinking to me, but I obviously hope I'm wrong. And "late Q4" could mean December 20th!
Oh, I agree. I've said many times I'm not optimistic that Tesla will get 5,000 Xs out this year. I Just hope they get 313 of them produced this year. ;-)
Biggest issue Elon seemed to be concerned about was the number of high quality parts their suppliers could provide to the plant. If even one part is in short supply it can slow down production of the entire line. I would imagine that production of the X would start off slow, and then ramp up as they can get their act together. Will be super quality conscious of the beginning production as those will be going to some of their best customers. As workers get experience on building the new model, they will become more efficient on getting them out the door to the thousands of pre-orders.
I am sure he much more worried about supplier quality since the SpaceX accident... In the earnings call he mentioned the second row seats and how hard they are to manufacture. I believe they made room in the factory for the company making the seats in the early Model S days. I don't know if they stayed there and if it is the same company making the new second row seats. I guess also this means they will be individual seats (as expected). He didn't mention a bench.