Oberon is an unusual case... he has IAA (insulin autoantibodies), which means that he needs a much higher dose of insulin than most cats, but his insulin needs can change suddenly because the antibodies can change how much they're binding up the insulin. Because Lantus is a depot insulin, it's hard to make quick changes to the dose. Using Lantus + R (short acting insulin) gives me more flexibility to adjust his dose quickly as needed. It's definitely not a typical approach, and I needed a lot of guidance from people with experience using R to get me started.