There's an interesting bit at the end:
"A. S. Nikolay Gerasimovich, sometime relatively long ago I was speaking with a pilot—a frontline veteran. Right after the war they flew in captured aircraft. And no matter how hard they tried, they were unable to attain the speeds the Germans had written in their specifications. The shortfall in speed was significant. In the end, they prevailed upon a German, a high-level specialist, and asked him, “Why this shortfall in speed? Are we using the engine’s capability incorrectly?” His response was that they would never achieve the target speed, because the German specifications showed the theoretical speed, and they were attempting to attain that speed on their instruments.
Nikolay Gerasimovich, in your view, is this possible?
N. G. Of course. We had a group of specialists with us from NII VVS. They were examining specifications and were looking at speed. “What speed is indicated at 7,000 meters? 780? Take away 100. And what about 3,000 meters? 700? Reduce it 70 km.” This is how they calculated the instrumented speed and, characteristically, almost always hit their target. Perhaps they knew something about our focus on speed."