They have formulas for adults & young bunnies depending on the age of your bunny. Drs. Foster & Smith also have free shipping on orders of $49 or more. It might be a good place for ordering for you depending on where you live. I'm on the east coast so I always have to pay to get food items shipped to me in a reasonable time.
That should be fine, hopefully your bun transitions to oxbow well. Sometimes with the junky food rabbits get spoiled on the extra sugars and fats and simply won't eat the healthier pellets. Good luck!