An early report may employ wording equivalent to “then He sent down.” The Prophet's recognition of the force of an existing verse, a ruling drawn from it and the first revelation of a new verse are different matters.
Where a narrative concerns clarification or an understanding made present to the Prophet, the wording alone need not settle the question of a fresh revelation. Its chronology and surrounding evidence are also relevant.
This is particularly important when the same verse is associated with several incidents. Each valid application need not be explained by positing a separate occasion of revelation.