O'Brien and Hennessy

One of my great grandmothers was Margaret O'Brien, the daughter of Patrick O'Brien and Johanna Hennessy. They married in Knockanore Parish, Waterford, on 24 Jan 1841, and three children were baptized in Knockanore Parish (James, 1845; John, 1848; and my great-grandmother Margaret, 1853. The residence of "Scart" was recorded on my great-grandmother's baptismal record (but not on any of the others.) Then three more children were baptized in Cappoquin, Waterford: twins Johanna and James, 1857 (I assume that the first James died young) and Mary in 1860. My question is, does anyone know if there was a reason the younger children were baptized in a different church parish? Does it indicate that the family moved? Or did something happen to the church in Knockanore in the 1850s?

My great grandmother emigrated to the US when she was a teenager, but family members wrote down that she remembered seeing Mount Melleray as a girl.

There was also a sibling named Ellen, for whom I cannot find a birth record, who emigrated to Walpole, Massachusetts, as did my great grandmother. Ellen was born about 1843.