I've done my own tests on this as well.... My rats and mice ate more of the doggy bag food, and had fewer and smaller litters on it.
The rodent block costs just slightly more, they don't inhale it like it's crack, and my litters are bigger, and I have less cannibalism.
I buy 40 bags(1 ton) of rodent block at a time, every 3-4 weeks. They more you buy, the cheaper it is... I get it for under $18 a bag when I buy in bulk. As opposed to buying from the same distributor, a couple bags at a time for $24 a bag... Even at $20-25 a bag, it still saves you money in the long run...