You forgot to add a zero on all of the cell sizes. For example, the 256k source cell is really 25.6k, and the 1k cell is just 100 bytes.

This is intentional, but admittedly pretty clumsy due to a lot of compromise with another maintainer more familiar with Ars Nouveau at the time. Keep in mind that one "byte" for a Source cell corresponds to 1,000 Source.