I agree the recommended RDI here is too high, and they don't let you target more than 1 lb/week in loss. However, when you calculate your RDI, you can ignore their recommendation and just enter your own target, that makes sense for you. They told me to target 2,500 but 1,600 is working much better for me.
Goal 1 - Run half marathon in early June (run not walk)
Goal 2 - Drop 100 lbs total before my birthday in late June