It isn't about dividing by two (30 to 15 might be a bad example). It's about ordering the sections based upon their number, but being allowed to skip numbers.

It is reminiscient of BASIC, where you had line numbers to control the order of your lines. You could number your lines 1, 2, 3 and so on, but a smart programmer would number the lines 10, 20, 30--skipping numbers which could later be used if you realized you needed to insert a line or two between existing lines (editors were bad in those days, and just renumbering all your lines wasn't really an option).

Personally I think this would be a good solution, especially if the lines were actually renumbered before being displayed to the user (or for internal storage), so that each time you examined the page you'd have the extra space in between numbers again. Having two boxes with the same number isn't a problem if they're renumbered before storage, since the system would just do a sort and renumber, which would remove the conflict (the order of the nodelets with the same number might be wrong, but if you give two lines the same number you can expect that you might have to do some futher work to have things the way you really want them).

Update: Ah, I see tye has already implemented something (that's what I get for not reading the whole thread before writing). I'd say go ahead and replace the old interface...can anyone prefer it? Or there's the usual make-it-a-poll option...