I'm relatively new to the game and boy it took me long to figure out that manufacturing and production are not the same thing. It was mostly because the game confuses the two in presentation (not mechanics). AFAIK (total) production has its own icon (stack of yellow cubes). But technologies that modify total production present it with manufacturing icon (orange hammer). And also when you got a planet selected in the little information window at the bottom of the screen the mouse-over tool-tip for manufacturing says its total production. I broke my head trying to figure out why the terran technology specialization improving total production by 1 point gives a fraction of that 1 point to "total production" (total manufacturing really) listed in planet information widget, because the game made me think these things are synonymous.