Library /sys$common/syshlp/pca$help.hlb MERGE, Qualifiers, /SINCE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /SINCE="time-spec"
       /BEFORE="time-spec"

    Sets the lower and/or higher limits on the collection times of
    the SPM data being merged. These optional qualifiers can only be
    specified together with the /SPM_PROCESS_ID qualifier. The time-
    spec parameters must be enclosed within double quotation marks ("
    ") and must be valid OpenVMS absolute date/time specifications,
    as described in the DCL Concepts manual.