Hydro plant shouldn't be getting enough water

I've been fooling around in Editor Extensions with some beaconed setups to see if they are actually possible to run in a real setup, and I ran into this oddity. It should require 4080 water/sec, but is being fed by only 3 offshore pumps (1200/sec each for 3600/sec total), and yet it never skips a beat. Anybody have a clue why?

Why does this work?

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