Library /sys$common/syshlp/nclhelp.hlb set, dtss, error_tolerance  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Default: 0-00:10:00.000    Value: 0-00:00:00.500-99-99:99:99.999

    Specifies the maximum separation allowed between the local clock
    and the computed time before synchronizations become abrupt
    rather than gradual (monotonic).