Specifically Tesla has explained the reason for a.
That explanation may have made a modicum of sense in 2013 when Tesla was trying to deliver 5,000 cars per quarter, worldwide. It rings somewhat hollow in 2017 since Tesla has been delivering 20 to 25 k cars/quarter for about two years. It borders on the nonsensical for 2018, since Tesla has ambitions of delivering 500,000 cars. Well-planned logistics and relatively steady state deliveries in all markets are far more efficient than quarter-ending fire drills.
As for c, besides guiding gross margin for M3 into 2018, I don't know what people are expecting.
Gross margin projections do not provide sufficient information about Tesla's ability to repay its maturing debt while funding its previously announced capital expansion plans for Superchargers, Service Centers, GFs 3 through X, and new products like Semi-trucks, model Y, solar roofs, etc. I submit the investment community expects guidance about more meaningful metrics like net income and cash generated from operations. You might consider listening to (or reading the transcript of) the SolarCity May 2016 conference call in which the investment community lost faith in the Rive cousins ability to ever make a profit. IMO, it was after this CC that Elon recognized he had to bailout SCTY with TSLA's shareholders' money.
As for b, you can call Elon's style Bob and weave, I interpret that as Elon always thinking in terms of a range of possibilities, and adjustments on the fly, to me that's a strength, not a weakness or fault.
You may be indifferent to the Q&A on CCs but I suggest you watch the share price action between the filing of the SH letter and the end of the CC. (The share price will also react to the filing of the 10Q about a week later when more details will be disclosed.)
Tesla has a tough enough time fighting the traditional automakers, oil money paying off biased media, and naysayers on the wallstreet. If you're an investor, the main reason you're investing in Tesla should be because of Elon. If you don't trust Elon you should get out of TSLA, if you do, then get off his back and let him do his job.
Please spare the "Elon is a victim" sop. I do not purport to be a TSLA investor. I trade shares for entertainment because it is volatile security that generates "pin action." Like Elon and battery chemistry/formats, I'm totally agnostic about this site's dogma. (Although I was initially attracted to the shares as a way of playing the EV alternative to personal transportation.) I'm in and out of positions frequently, and have been whipsawed in both directions more often than someone with incontinence visits a toilet.
Whether I trust Elon is immaterial. What I, and everyone who trades this company, are trying to figure out is how long will the investment community continue to trust Elon by funding the growing operating losses? Will it be long enough for operating leverage to finally make a difference?? In this quarter Tesla delivered the most vehicles ever in history, and it's also likely to report the greatest bottom line loss ever. The "market" is sending mixed signals about its trust of Elon. In August 2016, SCTY tried to float $124 MM of 18 month 6.5% coupon notes; the market passed so, Elon and the Rive cousins bought $100 MM of the offering. However, in August 2017, TSLA sold $1.8 billion of 5.3% coupon 8-year B-/b3 junk notes, after raising $350 million in equity and $850 million in convertible notes in March 2017.
My expectation is that the "market" will balk at additional capital infusions until Tesla demonstrates it can produce and sell the M3 profitably (SMP part deux is meaningless unless the M3 is a financial success.) Consequently, I prefer more true transparency and candid information to help me set positions in either direction rather than meanderings about "the range of possibilities." I recognize YMMV but as Rodney King asked "Can't we all just git along."