Biblical Update - Moving & Firing

UNDER Neil Thomas's biblical rules in Ancient & Medieval Wargaming it is stated that "close-order* troops may never move and fire."

Nevertheless, a special rule for the Assyrian army allows its close-order infantry and cavalry units to fire with half their bases even after moving.

I have more-or-less kept this special rule in that I am allowing Assyrian professional close-order infantry and close-order cavalry to move and fire.

Moving on to open-order troops, he states that open-order infantry, open-order cavalry and light chariots may move and fire "under certain circumstances."

1. Open-order infantry armed with javelins may throw their javelins either before or after moving.

2. Open-order cavalry and light chariots armed with bows may shoot either before or after moving.

3. Open-order cavalry and light chariots armed with javelins may split-move, ie shoot at any point during their move.

However, no unit may shoot if charging, ie intending to force a melee.

I understand why ordinary close-order infantry armed with bows are not allowed to move and fire, but why are open-order infantry armed with bows the only open-order troops unable to move and fire?

This seems to me a clear anomaly, and I intend treating open-order archers the same as bow-armed open-order cavalry and light chariots, ie by letting them fire before or after moving.

Egyptian open-order bowmen

*He uses the word "heavy," but "close-order" is a better term, as I have explained before.