Commercial construction specifications are done in this way as well. So all electrical specifications are in division 16000 (or 26000 nowadays) and subdivided from there.
This method of only being two levels deep is interesting. If it works, that's great, but there's nothing to stop you from going three if required, e.g. 10.20.30. But keeping everything constrained has value in itself, if only in that it forces you to think in larger discreet chunks.
This method of only being two levels deep is interesting. If it works, that's great, but there's nothing to stop you from going three if required, e.g. 10.20.30. But keeping everything constrained has value in itself, if only in that it forces you to think in larger discreet chunks.