I have been quilting for over 30 years and lines that cross over already stitched lines, still give me trouble. I find my Machingers gloves help and I make a frame with my hands around the needle gently pulling outwards when I come to an intersection. It may be time to reevaluate your quilting design. Can you SITD lines one way and instead of SITD the opposite way, quilt little motifs between the lines?