Claude, most FSL has a under stitch design - that crosses back and forth from one side of the design to the other - LACE how ever doesn't have those sort of stitches - do you have a stitch simulator with your program on your PC - I would suggest allowing it to run through the design - also there is generally a satin stitching on the outside of the design and the lace usually doesn't need that. Wish you luck and hope your FSL is just that - if that is what you are hoping for - you can also tell us what the name of your design is and the designer - someone of us may recognize it - or you can ask the designer?

If you can't have a look in software, you could stitch it out on tulle or organza and have a close look at the pattern. Are there stitches that are unconnected and would form loops if stitched on wss? That might tell you it's not FSL.