I don't think this is something you should specifically focus on, especially if you're capable of doing other content. In the same amount of time spent I'm sure you could have gotten a weapon and mirror from Leviathan Ex and had a "true" i100 weapon. (the Atma doesn't even receive a bump in stats, just a new model)

I do this particular form of content in short spurts after working on other things for the day. If I have an hour left or so before I need to log out for the night I'll go pop in a zone for a bit and try my hand at it. Sometimes I get lucky, other times I don't.