Apparently, the only way to advance the "last altered date" field of the root directory is in making a change to the file system which has the effect of allocating/releasing storage space.
ACTION_SERIALIZE_DISK sets both creation and last-modified dates in the root block. It's possible that due to it doing TR_GETSYSTIME once for creation and once for last-modified fields, that the last-modified time is one or more ticks later than creation.
ACTION_RENAME_DISK changes the volume last-modified date (at "size-10") only.
What changes the root datestamp at "size-23"?
