I'm still not sure what type of ribs you are talking about. Your last description indicates that not only are they way overcooked, they are burnt. If you are cooking spare ribs your cook times are good, and overall your temperatures are not that far off, for the 3-2-1 method. If your temperatures are too high, you may get ribs that are mushy but not burnt. Also your are using less cook times at the beginning and end; so why they are burning I don't understand. If you are using the digital model, that could account for too high of a cooking temperature, but the ribs should not even be that close to burning the way you have described. What do the ribs look like before you wrap them, and after being wrapped? If you are using poor quality ribs, that have a lot of shiners (the bone showing through the meat side),that could be a cause. Get your ribs from someplace else.
Low and slow is the only way you can go in the Bradley. When using charcoal I cook my spare ribs at 275, using a 3-1-done method. There hours of smoke/naked, 1 hour wrapped, and 30 - 40 minutes resting (sometimes a little further cooking is required). This gives me pull off the bone/competition ribs. If I screwup and overcooked them, they become fall off the bone - not burnt. So that is why I don't understand why your ribs are not only dry & overcooked but are burning. Other than what was suggested by Orion; use your same temperatures and cut down your cook times - check the ribs doness before and after wrapping, or use 225°F through the entire cook. If you experiment in temperature and times, only change one variable at a time. Remember ribs are done when they are done so monitor them. Time is just a guideline, so take them out when done. It couldn't hurt to add a little butter, and honey when you foil. Make sure the ribs are meat side down.