I find that weapon range in D&D is very... suspicious. There is an old OSR blog where they presented some very conclusive evidence of where Gygax got his data for bow ranges, and how said data was not interpreted correctly (basically the error is is the effective range vs a mass of enemy vs the effective range vs a single person). Sadly I have lost the link. (edit: if anyone has it...)I just looked up the throwing distance of an atlatl, and 300 feet seems to be a common distance listed for it so the 80/320 seems suitable as the range.
Because of this, I find relative range between weapons to be a good guide. It "feels" to me that a bow should have a longer range than an atlatl.