The most common problem encountered when setting up a LR-JET Weight & Balance profile is that you have entered the empty weight and moment, and the calculated CG is some ridiculous negative number. What went wrong?
Frequently, the weight and balance data you see in the AFM has the moment expressed as Moment/1000. A LR-JET Weight & Balance profile needs the actual moment in order to calculate the CG correctly. So if your data is Moment/1000, multiply by 1,000 (move the decimal point three places to the right) and enter that number in the moment field. You should now be seeing a CG that looks a lot more reasonable.
Why not set up the application to use Moment/1000? While Moment/1000 is commonly used, that is not always the case. A user might be looking at the raw data from a new weight sheet where the moment hasn't been reduced. Less commonly, the moment might be reduced by another factor, say 100 or 10,000, so the most reliable way to set up the application was to use the unreduced moment value.