Ok, so
Well in the two that you use, one shout are words of power while the other was not, at least for dragons. There is nothing forcing the first shout to have any effect, so and so comes of his own free will. Now we do learn dragonrend just by hearing it but I take that as a mortal already knows what means to be Mortal, Temporary, and Finite. We just needed to learn the translation. While the last one is something from the dragons (I'm guessing) there for based around their own knowledge which you will need to steal to use.
Just a guess.
I remember a TVtropes fridge brilliance explanation for summoning Odaviing.
The theory goes that calling Odaviing isn't an actual Thu'um shout; instead, it's just you calling his name very loudly, leaving you very hoarse, hence the long cooldown.
Yeah, Odahviing and Durnehviir make sense because you're just calling their name - no knowledge of how it really works needed.
Dragonrend works, too, because as someone in a mortal body, you inherently understand the concepts that make the Shout - Mortal, Temporary, Finite. These concepts are literally impossible for dragons to comprehend in the context of themselves (which is a context you make when you hit them with the Shout), which is why it works so well. While Bend Will, like other Shouts, isn't really something you'd understand without Dovah knowledge.