On one hand it's just verbiage on the dealer's part. Here's what the website says for the Jewel: "The new Jewel longarm machine from Baby Lock gives you the joy of gorgeous and intricate quilting with the utmost creativity, precision and confidence." Note the term precision in there?
On the Crown Jewel the ad says there's something called "Precision Stitch regulated mode". So I think that's what the dealer might have meant - a different stitch regulator. Means nothing unless he tells you how it is better than the one on the Jewel, but maybe he doesn't know.
For longarms in general, you will find the term 'precision' used in relationship to almost anything (even leaders!) and all of them think they have it. LOL