For digging and dividing Crocosmia, most (60%) says to dig in early Spring, then others (40%) says to dig in last fall. So which is correct?

I think it may be safer to dig in late fall. In early Spring, there is the possibility that the corms have started growing already. Then that is not a good time to dig.

I think as long the corms are dormant, and the ground is not frozen, then there is no difference....