Library /sys$common/syshlp/dbg$help.hlb DEBUG, Language Support, BASIC, Evaluating Expressions  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Expressions that overflow in the BASIC language do not
    necessarily overflow when evaluated by the debugger. The debugger
    tries to compute a numerically correct result, even when the
    BASIC rules call for overflows. This difference is particularly
    likely to affect DECIMAL computations.