I started my pup on Purina Pro Plan Performance 30/20, the vet suggested that I should get the PPP Puppy food and mix the performance in until I get rid of it. Will the mixing of the two foods give my dog expectations to continue this in the long term? Both bags are the 37.5 lb bags... it's going to take a while to get rid of the Performance food. Another problem is that the recommended daily feeding amounts are different, I guess this is due to the calorie content. Any advice is greatly appreciated.