The slant line regulation was amended in 1995, causing an awkward feature that some part of height-limit becomes more restrictive with setback. To remedy this situation, two rationality conditions are imposed:(1) deregulation condition with setback; and (2) non-decreasing height-limit condition. The hinge point and the origin of distance upon which the slope of the slant line depends are recommended to coincide to ensure the flexible regulation while satisfying these conditions. Two amendments of the current regulation are proposed.
