VMS Help DIFFERENCES, Qualifiers, /MAXIMUM_DIFFERENCES  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /MAXIMUM_DIFFERENCES=n

    Terminates the DIFFERENCES command after the specified number of
    unmatched records (specified with the n parameter) is found.

    The number of unmatched records is determined by finding the
    maximum number of difference records for each difference section
    and adding them together.

    If the DIFFERENCES command reaches the maximum number of
    differences that you specify, it will output only those records
    that were detected before the maximum was reached. Also, it will
    output, at most, one listing format and return a warning message.

    By default, there is no maximum number of differences. All
    records in the specified input files are compared.