Aren’t the predictions moving targets based on where you are at the moment and what you plan to do in the future? I don’t remember what it said on Dec 5 when I started Base but I assume the numbers change with each BT/FS update. Perhaps they narrow as you get closer to TED. When I looked during Peak the prediction was X and when I finished up and had my ending BT during post-event the number achieved was X-4 (not 4% but 4).
In any case I started at X and 4 months later the result was X + 38%. 
Perhaps it’s ~10% per month and dependent on ramp rate and whether you can handle the TL.