This is a fascinating question. It's incredibly rhetorical, and I've sat here pondering it for a bit. It's very easy to reply to this question with "well I suppose it depends." And then tack on "What do we consider 'doing good/more good'? What is the nature/species/alignment of the lives being saved, and how are are they equal? Who decides which two lives are better to save than the one, if it's somehow decided that one is better than two? Does the two lives vs one life involve picking between the same two lives, or is it an entirely different set of lives?" and a whole mountain of other questions. It's like asking a magical wish granter to "save two lives" and it does something predictably spiteful like saving two single celled organisms and causing a kitten to die. Thanks for giving me that to chew on.
One glaring obvious problem with the EA people, is that they double count.
Say I give money for bed nets, and the bed nets save 100 lives.
But say I only gave that money because Eliezer Yudkowsky convinced me to. Was it really him that saved 100 lives? Or do we divide them between us somehow? How many should go to the people who actually distributed the bed nets I paid for?
You'd think the EA people would have good answers to these questions. Or at least, any answers. But they don't. Not any consistent ones. They cheerfully double-count in all their most famous arguments.
I don’t think EAs are focused on assigning credit here. It’s very consequentialist; they would say “it doesn’t matter who saved the 100 lives, it matters that they were saved.”
It matters if the 100 lives are suddenly 200 lives when you sum them up. It matters for decision making. It matters for questions like "should I rather do it myself or start a foundation to convince as many other people as possible to do it".