回複：do not understand; ask apt.

It is the strange wording by the PTO. The actual sentence is this:

It is OF NO moment that the end of that period for diligence is fixed  by constructive, rather than an actual, reduction to practice.

This meant, the ending of the diligence period is marked by either constructive RTP, i.e., filing an application, or an actual RTP. Long time standing PTO policy.