Hmmm.... That's seems odd. I have an OS .55AX in mine which only weighs about 1 oz. more than the .46AX. Considering the engine is only about 6" behind the CG, 1 oz. isn't much. Mine balanced perfect at 10.5" from the wing leading edge at the fuse with no added weight. I have the Rx and battery right behind the nose gear block. If I had an additional 1/4 pound of tail servos I would certainly need to add nose weight.