I make 460 units of fuel. My generators consume 400 units. And yet they keep running out of fuel... What gives

I make 460 units of fuel, I pump it in to mark 2 pipes, and deliver them to two "branches", both feeding 5 generators on each side, for a total of 20, for a total of 400 fuel consumed.

I put two mk 2 headlift pumps at the start of both "branches" to hopefully increase pressure.

I'm out of ideas as to how to make it 100% efficient.

Although, that lamp back on my base that kept emmiting light even after detached from the power network entirely, makes me suspect I might be experiencing some bugs.