Thanks, I totally missed that - good to know.

that's pretty vague, first of all last month is in the last year; even if we assume in the last year to mean longer than a year ago the or so part can also imply leeway before that year is out (this is of course a regional usage, most places in U.S I think take last year or so to mean a year or more)

usage of vernacular speech while humanizing also has the effect of making things inexact.