In JY's third revision of TLBB, XL18Z has been increased to 28 palms. Then, Xiao Feng and Xu Zhu shrank the form to 18 palms, keeping only the essence and removing repetitions. Do you think JY's modification of XL18Z in TLBB from 18 to 28 palms serves a useful purpose? What is JY trying to tell his readers through this change?