لِأَنَّ الْمَعْنَى الزَّائِدَ فِي الْحَدِيثِ الْمُحْتَاجَ إِلَيْهِ يَقُومُ مَقَامَ حَدِيثٍ تَامٍّ،
For an additional meaning that is needed can, in its significance, stand in the place of a complete report.
“It takes the place of a complete report” does not mean that an extra word becomes an independent Prophetic report. It means the scholarly value of the needed addition may warrant presenting the report again as though it supplied a separately important item.
For example, a second transmission may preserve a qualification to a previously general statement. That qualification needs analysis before both transmissions are taken to convey the same unqualified meaning.