My answer is a little different, since I pretty much consider any round that goes down range as opposed to somewhere else, to be "accurate".

When I test loads its more to establish a ballpark for pressure/recoil/velocity... none of which I actually measure any way except subjectively, anyway. One carefully measured and loaded round at each amount of powder is all I need on first blush. If I go on to a second level of more refined testing, then I switch to a larger number of rounds with each specific load. But, when I'm doing this, I'm in or near uncharted territory. In the manner that you are referencing, if I were attempting to attain long range accuracy, I would be loading lots of rounds. I mean, isn't it the journey as much if not more than the destination?