if your work looks better on quilted fabric then by all means go ahead- after all it is your project- I wonder though---if it is already quilted do you not stitch all the way through when appliqueing? or do the applique stitches add to the quilting stitches on the back? I would love to see some of your applique projects you have done this way. there is nothing wrong with trying/finding your own techniques for projects- if you achieve the outcome you wanted/like go for it...then come back & teach it to us.