We have 30 items (12 per page), and we're viewing the item 25.
After switching to a view of 9 items per page, the item 25 is located on the 3th page.

1	13	25		-->		1	10	19	28
2	14	26		-->		2	11	20	29
3	15	27		-->		3	12	21	30
4	16	28		-->		4	13	22
5	17	29		-->		5	14	23
6	18	30		-->		6	15	24
7	19			-->		7	16	25
8	20			-->		8	17	26
9	21			-->		9	18	27
10	22
11	23
12	24