Difficult to say without seeing the whole document but one possibility is that the registrar has made some sort of alteration on this entry and the note refers to that.
If the registrars initials match with the W W M and there is some even slight alteration then that could be it.
NB the 'five' could be the cumulative number of alterations on the entire page, not just this entry OR it 'may' refer to the column no. the alteration in is - not too sure about that part.
Boo