These are offspring, that didn't make it to 16h, of 16h or greater stallions, and ARE Holsteiners, but not 16h. If they were stallions, they would still be branded Holsteiner, but not approvable as stallions. That's the difference.
The Trakehner people consider themselves a breed too but still allow arab & TB, yet you have to have some Trakehner blood to be a Trakehner.
The Hanoverian people here in the US for a long time required 50% hano blood but I think they are/did away with that requirement - and they didn't have it in Germany.