* actual_IN, actual_OUT  -- actual punched times.
* sched_IN, sched_OUT    -- scheduled IN/OUT times.
* effective_IN, effective_OUT  -- effective IN/OUT for computation
* IN_round  -- maximum number of minutes for which an early IN punch
*              will still count as if it was punched on-time.
* IN_Grace  -- maximum number of minutes allowed for punching IN late
*              but still have it count as punched on-time.
* OUT_grace -- maximum number of minutes allowed for punching OUT early
*              but still have it count as punched on-time.
* OUT_round -- maximum number of minutes for which a late OUT punch
*              will still count as if it was on-time.
IF BETWEEN(actual_IN, (sched_IN-IN_round), (sched_IN+IN_grace)) THEN
    effective_IN = sched_IN
ELSE
    effective_IN = actual_IN
ENDIF
IF BETWEEN(actual_out, (sched_OUT-OUT_grace), (sched_OUT+OUT_round)) THEN
    effective_OUT = sched_OUT
ELSE
    effective_OUT = actual_OUT
ENDIF