the only reason the DCs have pinpoint accuracy is because I gave them that accuracy. I set the depth precision to 2.5m. Why did I do this? Because the game gives no way to change that (or many other items) based on year. So let's say I set the depth precision to 10m. Then in '42 you'd have DCs being dropped with 10m depth precision (set depth +- 10m). Very unrealistic. I had to compromise and that compromise was giving them accuracy at the beginning years.
Now that I've just put my thoughts on paper it has occurred to me that there is a way to change accuracy via year. I would have to make new guns and just setup the controllers differently. Ah but we can't do that yet as we are unable to clone or import .GR2 files. So we're left at the current compromise for now