I have yet to hear instrumental breaks be anything other than interruptions to a narrative and the longer the break, the greater the interruption

One striking example of using an instrumental break to great effect is in Mr Fox's 'The Gypsy'. The story is quite a simple one but well told in the usual Bob Pegg style. Between the lad learning where the Gypsies are camped and him arriving at the site, the instrumental break portrays his urgency in crossing the Buttertubs Pass pretty well and, in my opinion, enhances the narrative. I am sure there are other examples.

Cheers

Dave