There may be a problem with your DSM. If you can, try your walking foot. If both fabrics are cut to length together, they should end up at the same length when stitched. I do the same as Tartan does. I cut an extra 1/4" so I can then trim down to size after pressing and starching. You just have to find what works best for you. Have you had your machine serviced recently?? DSM are just like cars. Most need an annual checkup and cleaning (places that we have no access to). Good Luck.