Often it becomes important that we make those distinctions in chronology clear to the reader.
Speakers frequently refer to the past or to past events when they are talking to a reporter.
Similarly, when the speaker uses the present perfect tense we change it to the past perfect to make clear to the reader that the speaker was referring to an action completed earlier than the time of the interview. If the context of the sentence shows the order of events, the past perfect tense is made unnecessary. But because the speaker also told us when he had been sick, we could avoid the awkward past perfect had had and still make it clear that we are talking about two different points in time. When sources use both future and future perfect tenses, we cannot cast all of their comments in the conditional tense, because to do so would alter the speaker's meaning as well as confuse the reader. In any event, I will have introduced it before the deadline for new bills.