It is not grey but it is not obvious, the rule needs to be correctly interpreted and note that the CAT.POL.A.230 directs that the landing mass refers to CAT.POL.A.105A, is at the start of the takeoff or an inflight re-plan. That is it is a planning function.
CAT.POL.A.230 Landing — dry runways
a) The landing mass of the aeroplane determined in accordance with CAT.POL.A.105(a) for the estimated time of landing at the destination aerodrome and at any alternate aerodrome shall allow a full stop landing from 50 ft above the threshold:
1) for turbo-jet powered aeroplanes, within 60 % of the landing distance available (LDA);
CAT.POL.A.105 General
(a) The mass of the aeroplane:
(1) at the start of the take-off; or
(2) in the event of in-flight replanning, at the point from which the revised operational flight plan applies, etc