The larger rat size was the convenience factor I was referring to.
The snake digestive system is inherently adapted to handle whatever it can get. One 100g rat is not inherently better than two 50g rats.
The differences in percentages of those values are statistically meaningless between rats and mice.
There is no study showing what the requirements for ball pythons are. Without knowing the requirements, how can you say which is better, ie why is the ash % of rats over mice better?
Tons of BP's refuse to eat rats and are fed solely mice. Tons of BP's eating mice are just as healthy as the ones that eat rats.