Nissaggiya 28 has been translated and understood inappropriately by using the commentaries' explanations. In commentaries, the difficult word in the text kattikatemasipunnama is explained as the full-moon of the first kattika (pathamakattika-), that is, the third month [of the earlier rain-retreat (vassa-)]. Rhys Davids--Oldenberg, Horner, and Akira Hirakawa follow this explanation. They translate and explain Niss. 28 as a rule which allows monks to accept the robe as a special gift (nt. accekacivara-) ten days before the end of the earlier vassa-, and to keep it up until the robe-season (in text yava civarakalasamayam during the robe season!). The word kattikatemasipunnama, however, means the full-moon of kattika, the third month [of the rain-retreat (vassa-)], that is, the full-moon at the end of the later rain-retreat.
Nissaggiya 28 applies to the monks who are spending the later vassa-. For example, when a layman who is going to start a journey or going to war wants to give [a robe as] the “gift for the rain-retreat” (nt. vassavasika-) urgently, by applying this rule the monks can accept the robe as a special gift (nt. accekacivara-) during the last ten days of the later vassa-, and keep it up during the robe-period (yava civarakalasamayam). The period of the last ten days is supposed to be fixed in order to follow the ordinary time limit for keeping a surplus robe (Nissaggiya 1) and for making a robe (Nissaggiya 3). And, this period is appropriate for the climate as well. The purpose of this rule is to make it possible to accept and to keep up the gift for the rain-retreat in appropriate time and period, which should be attained after the vassa- in principle. This rule is supposed to be enacted on condition that the monks generally make robes after spending the period of the vassa-.