Wouldn't it make sense to say "Fire at will!" as soon as possible? Individual archers would kill more people in the time spent waiting for the commander to say "Fire!" again and again. It's a confusing questions, I know, but it's something that has been on my mind for a while. Why not unleash hell at first chance?
Where are you drawing your assumption from that it was fire, fire, fire...fire at will?
hi! these posts won't answer your question head-on, so there's lots of room for a direct response, but you may find them of interest since they touch on the tactics of volleys
I doubt the commander would say "Fire" at all, as this would be anachronistic if applied to archery. "Fire" was a term that was applied to firearms. The command to archers would have been, "Loose", or "Shoot".