It says they could be pseudorandom and non-monotonic. Or it could be monotonic and non-random. These are completely disjoint cases! "X or not X" is tautological. And there is no way to determine which (e.g. there could be a flag that indicates this mode, but there is not).

To be clear, the standard should be amended to resolve this ambiguity. Say the last bits MAY be monotonic or MAY be pseudorandom. Or add a flag that indicates which.

As there is currently no standard way to interpret these bits, I feel perfectly justified in using the a few of the least significant ones to encode additional information.