Yoy have to remember one thing: archer is main target for enemies cav, speed runners, other archers, and x-bowers.
IMO 3 ath is too low to be able to keep shooting and following your team, changing your positions, avoid cav and etc.
6pd is enought for archer, it's better to be mor accurate, because archer who is not hitting enemies is just useless.
I tried many bulids (11 gens of archery) and best for me is 18/21 with 3 ps.
I play on battle servers, and sometimes siege.