Do I (US citizen) need a visa for flying OUT of Kazakhstan via Russia?

I'll be flying into Kazakhstan from Europe, and then flying from Astana to Tokyo with a stop in Novosibirsk, Russia. The Astana-Novosibirsk and Novosibirsk-Tokyo legs are on the same airline (S7) and the stop is only a couple of hours so I thought that I wouldn't need a visa.

However I then read that

Please note that if a foreign citizen travels across the territory of Russia to the countries of the Customs Union (Belorussia, Kazakhstan, Armenia, Kyrgyzstan) he is required to apply for a transit visa, unless he’s a citizen of countries eligible for visa-free travel to Russia in accordance with bilateral agreements.

(cf Do I need a visa for Russia if just transit through Moscow?)

It seems that the reason is that flights between Russia and Belorussia, Kazakhstan, Armenia, or Kyrgyzstan are considered domestic flights, so if one passes through Russia on to one of those countries he essentially enters Russia. However, I assume that his doesn't apply to flying OUT of one those countries via Russia? Since even if the Kazakhstan-Russia flight is considered domestic, I'd only ever be going OUT of Russia rather than IN?

Thanks!