It would be quite interesting to know whether the decision not to install SCR was taken before the optimizations were done. Because that actually would be a plausible theory of why this happened that would jive with my experience of the automotive industry.
If it was basically one asshat manager saying that 'yeah, we're going to do this IN SOFTWARE without using SCR! And save MONEY!", then I can see exactly what happens next. Engineers go "good grief, what an ass, this is going to suck in most cases". Then they get to figure out basically any and every situation you can reduce effect and write logic to accomplish it until they reach required targets. And it just so happens that the idiots designing the benchmarks have produced benchmarks that look nothing like reality so of course they'll get completely different results than what happens when you're not driving the car under specific ideal conditions.
Of course, if that's actually it, then it's not even intentional fraud. And actually using those optimizations would be a good thing as they obviously do reduce emissions in certain conditions where power might not be needed, it's just that they should be using SCR as well. And the benchmarks should be updated to reflect real life situations.