I agree that's part of it. But on the other hand, if you look at COGS on energy it's hard to see how D&A on that segment is more than a few tens of millions. Likewise for miscellanea. This quarter we'll have a better picture.
Tesla could be basing some D&A and other overhead expense allocation between Automotive and Energy on segment revenue.
In other words, as total D&A remains relatively flat in the coming quarters, surging revenue from the Automotive segment could indirectly improve Energy segment's gross margin.
Let me illustrate this with a simple example:
Period 1
Segment A rev: $90
Segment B rev: $10
Total D&A: $20
D&A allocation to Segment A: $20 / $100 x $90 = $18
D&A allocation to Segment B: $20 / $100 x $10 = $2
Segment A gross profit margin assuming $50 direct costs: [$90 - ($50 + $18)] / $90 = 24%
Segment B gross profit margin assuming $8 direct costs: [$10 - ($8 + $2)] / $10 = 0%
Period 2 - Double Segment A revenue while keeping Segment B revenue and D&A flat
Segment A rev: $180
Segment B rev: $10
Total D&A: $20
D&A allocation to Segment A: $20 / $190 x $180 = $19
D&A allocation to Segment B: $20 / $190 x $10 = $1
Segment A gross profit margin assuming $100 (double $50 above) direct costs: [$190 - ($100 + $19)] / $190 = 37%
Segment B gross profit margin assuming $8 direct costs: [$10 - ($8 + $1)] / $10 = 10%
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This example illustrates how Segment B's apparent profitability can improve only because of the increase in Segment A revenue.
Retail investors and small-time institutional investors, who do not have intermediate accounting education and related professional experience, will not understand why this happened, as both groups only look at the red ink at the bottom-line, and reason up from there on everything related to Tesla - i.e. the "Tesla is structurally unprofitable" rhetoric, which could not be further from the truth.
