As Tartan said, skipped stitches are usually a sign that the westalee ruler foot is a little too high. My PQ1500s (identical to the Jane) does best with the Westalee foot if it is just barely skimming the fabric. I found that the tool Westalee provides to help with adjusting the height of the foot leaves it too high off the fabric. You want the foot low enough that it is barely touching the fabric, but high enough that there is no drag/friction as the fabric is moved under the foot.
Rob