Xserver happens, at least it did, on the 1st of the month for servers who are 2 month of age or older at that time.

In other words, the amount of time a server does not have Xserver ranges from 2 month and 1 day to 3 month and 1 day. (or maybe exactly 2 to 3 month, somewhere around that)

S720 is opened on September 11th.

This means at last "checkpoint" of November 1st, it is not 2 month of age.