i find it interesting that the oxbow site sells the regal rat food as adult PET rat food.it seems to me that 14% protein and 4% fat are a bit low for breeders.
how long have you been using it? i guess if it works well that's all that counts.
sometimes i think that the popular "accepted" %'s are just a rough guide line.my rats seem to do great on a variety of different feeds i've used over the years.have fun!