How is AC11 rearranging them? Did you happen to cut/copy & paste any of them?
The only way I know to renumber cameras, is a tedious cut and paste workaround. You can cut the misnumbered cameras out and paste them back in, one by one. Then delete the extra cameras that ArchiCAD automatically creates.
Reall nuisance.
Nice part of the world you live in.
Cheers,
Link.