In my experience...
Big bullets, 500g and above, to be "competition quality" with extremely small weight variations need to be ladle poured. Smaller bullets, plinking bullets, handgun bullets....no advantage to ladle pouring.
Dozens upon dozens of folks have proved this "theory" time and time again by ladling a large number of +500g bullets and bottom pouring the same, then weighing and sorting all. The ladle pour bullets ALWAYS have less weight varience. I've not seen, read or experienced with my own testing anything to challenge this result.