Any benefit you gain from that is marginal. Better to simply focus fire on high value targets. When the two melee forces clash, run some archers out to the flanks to fire down the enemy flank. If you can, fire into their back with flame. It's highly effective.

If you don't have cavalry and they do, then you are at a distinct disadvantage. Try very hard to avoid this situation. Protect the archers flanking with your flanking infantry force (you do have those, don't you? If not, then it will be an attrition fest which will not generate that great of a kill ratio).