Although it is possible to have multiple lexicalizations in a partially lexicalized rule (which will exponentially increase the total number of rules), we observe that most of the time reordering is triggered by a single constituent.
as opposed to the general syntax-based reordering approaches, this strategy achieves a desired balance between broad rule coverage and specific rule match: when a fully lexicalized rule matches, it has strong influence on the permutation decision given the richer context.