518/533 ~= 97%, not 5%. I must be misunderstanding something somewhere. Explicitly, I'm saying that (per my understanding of that article) Tesla derived more income from selling emissions credits than from selling cars in that particular quarter (and, I think it's reasonable to assume, other quarters, given how overwhelmingly that seems to be their business model).
Even the emission credits being "pure profit" is misleading, given that the only reason Tesla can sell those is because of the cars/batteries/etc they are producing, so realistically the cost of producing those things should be deducted against the revenue generated by selling the credits.