I wish I could help you, but I never really did the research on the dog food vs. lab block question.
I fed dog food to my mice and rats for a while, and noticed that the mice tended to get tumors much sooner with dog food vs. the same mice fed with lab block. (Not very scientific, just personal observation, I have no data, and no proof.) Mice also tended to do better with block, so I feed them block.
Then I tried it with rats. I only tried 3 or 4 different kinds of dog food, some middle priced stuff, and some really cheap stuff.
I found that rats tended to eat more dog food than lab block, and pooped more, as well as drank more water (Maybe higher in salt?). It didn't seem to cause tumors as it did in mice, but maybe I just needed to do a longer term study, as I only tried dog food vs. lab block for 9 months or so in rats. The rats also tended to poop dry pellets with dog food, and their poop was healthier looking with lab block, albeit a bit softer. Dog food seemed to dehydrate them more, so I switched them all to lab block, and all was well again. I seemed to go through bags of dog food very quickly, and lab block lasts longer, and they seem to do better with it, so i stick with it.
Sorry I can't be more help.