The way I understand it . . . RDI already includes your deficit. Say your daily intake for maintenance should be 2800 (based on weight, height etc and how "active" you are), then your RDI will be around 2400 for weight loss. Remember you specify how active you are and if you want to loose or gain or maintain weight. Also keep in mind that the RDI does not take your exercise diary in consideration - thus, if you exceed 2800 by all activities you perform during day, it will obviously make your deficit bigger. However, the Diet Calendar will show you a NETT deficit or not - based on your exercises. All of this means you can go RED on the RDI and still have a deficit on the NETT Cals in the Calender.
. . . remain sane . . .