Munro's surprising ending in The Ottowa Valley

Alice Munro's story The Ottawa Valley in Selected Stories and published in the mid 1970s I think is another early look at the style that Munro would further develop and perfect over the next 40 years or so - on the surface it's another one of her stories written from a mature perspective looking back on the childhood of a young (10 years old?) girl who's perceptive and mildly rebellious (this is rural Canada, after all) - in this particular story it's about the narrator's memory of a childhood visit with mother and younger sister to cousins and family in remote Ontario (it's not a valley, there are no mountains, the perceptive narrator notes - what's the meaning of that? why do they call it a valley - it is a valley in some symbolic sense, whatever that might be). The story seems to be about meeting the various eccentric relatives - but that's just the surface. What it's really about are tensions beneath the surface, and Munro's way of gradually elucidating these tensions, slowly bringing them to the fore. The story is a series of scenes - nothing unusual there - but in Munro's fashion each scene changes the balance of the story - not just a steady accrual but a shifting and developing of point of view. For ex., the first pages describe the young girl's memory of the Toronto train station - they've evidently come into the city from a remote suburb, although this is never stated directly - and they were supposed to meet an aunt who works at "the best law firm in the city" - but the aunt never shows. The absence of the aunt becomes a trope in the story; when they get to the cousins near Ottawa there are some snide remarks about why the aunt didn't turn up - and the young narrator receives them, processes, recalls, but cannot exactly make sense of these remarks. And that's the nature of the whole story - there are social tensions glancingly revealed but just beyond the reach of comprehension of the child. Of course, the narrator, looking back, does understand - but she, the mature narrator, is trying to get at some aspect of the girl's relation with the distant, judgmental, misanthropic mother. Munro does something very daring and surprising at the end: she has a final short section in which she notes something like: I probably should have ended the story at the point where the mother was walking away from "me" (yes, we think - she could have - that would have been a very traditional, epiphonic ending) but she says she wanted to take the story one step farther - very unusual, an author stepping off from the story and commenting on her craft and her writerly decisions - but this is not just a post-modern trope - it's an author struggling with material, and also embellishing the character of the narrator by showing her still smoldering doubts and uncertainties. So typical of Munro - the everyday become strange and infused with meaning and potential.