I believe the reason is that most builders are not able to control paint weight. The fuses from ZNLine are lighter than the old fiberglass fuses. Lighter absolutely, not just by volume. They are much lighter and stiffer airframes. I have a Supreme that weighs 9.0 pounds. So not all current 2m airplanes are 10 or more pounds. I have a PL Partner that weighs 9.75 pounds, with a DZ. I did not do anything special to keep it light. I made sure that on both models I added less than 4 ounces of paint. And the paint looks good BTW.