You forgot to then convert the 0.549335952 inches to 13.953133 mm. To me, that is just a few MM. The difference between the calculated 1/4 wavelength and the 1 meter wire is consumed by circuitry paths and tuning of the RX. The major point here is that the RX is designed and tuned to operate at optimum with a 1 meter antenna wire. The Futaba Hi/lo's are broken down even futher into 2 groupings. While a HI band Futaba would function with a LO band crystal it would be further from optimum than Futaba wishes to operate and range would suffer.