A zine is not printed in reading order. Once sheets are folded into a booklet, page positions shift so outer pages, inner pages, and center spreads all land in different places on the press sheet.
If the imposition is wrong, the zine may still print, but the finished booklet reads out of order, places spreads on the wrong side of the sheet, or creates assembly mistakes during folding and binding.
Kumizine separates the production math from the design work. You decide page count, size, and binding style, and the app calculates the spread order before you start placing artwork.