Latest date for population isn't necessarily the preferred one, it can be a predicted one for a short timespan. For example Statistics Norway provide a 3 month expectation in addition to the one year stats. The one year stats should be the preferred ones, the 3 month stats are kind of expected change on last years stats.
Main problem with the 3 month stats are that they usually can't be used together with one-year stats, ie. they can't be normalized against the same base. Absolute value would seem the same, but growt rate against a one-year base would be wrong. It is a quite usual to do that error.
A lot of stats "sounds similar" but isn't similar. It is a bit awkward. Sometimes stats refer to international standards for how they should be made, in those cases they can be compared. It is often described on a page for metadata about the stats. An example is population in rural areas, which many assume is the same in all countries. It is not.
And while I'm on it; stats often describe a (possibly temporal) connection or relation between two or more (types of) subjects, and it is not something you should assign to one of the subject. If one part is a concrete instance then it makes sense to add stats about the other types to that item, like population for a municipality, but otherwise it could be wrong.
In general, setting the last added or most recent value to preferred is in general wrong.
And also, that something is not-preferred does not imply that it is deprecated. And also note the difference between deprecated and deferred.