Ok I realised that I have a scale plastic bow (actually Faramir's toy bow
) so I did some research this morning.
Looks like I'm more right than you are.
When I shot 1 arrow, it got like more than 2 meters far. When I shot 3 at a time, it wasn't even 1 meter.
When I was firing the stupid toy arrows, it all made sense to me. Something light (without much air resistance) goes much farther than something that's 3 times as heavy.
So there's no way you can create a lot more damage by firing 3 at once.