Art. 69

A penalty lower by one or two degrees than that prescribed by
law shall be imposed if the deed is not wholly excusable by
reason of the lack of some of the conditions required to justify
the same or to exempt from criminal liability in the several
cases mentioned in Article 11 and 12, provided that the majority
of such conditions be present. The courts shall impose the penalty
in the period which may be deemed proper, in view of the number
and nature of the conditions of exemption present or lacking.

NOTE: Penalty to be imposed when the crime committed is not
wholly excusable:1 or 2 degrees lower if the majority of the
conditions for justification or exemption in the cases provided
in Arts. 11 and 12 are present.

People v. Lacanilao (1988)
Facts: The CFI found the accused, a policeman, guilty of homicide.
       On appeal before the CA, the CA found that the accused
       acted in the performance of a duty but that the shooting
       of the victim was not the necessary consequence of the
       due performance thereof, therefore crediting to him the
       mitigating circumstance consisting of the incomplete
       justifying circumstance of fulfillment of duty. The CA
       lowered the penalty merely by one period applying Art. 64
       (2) appreciating incomplete fulfillment of duty as a mere
       generic mitigating circumstance lowering the penalty to
       minimum period.

Held: CA erred because incomplete fulfillment of duty is a
      privileged mitigating circumstance which not only cannot be
      offset by aggravating circumstances but also reduces the
      penalty by one or two degrees than that prescribed b law. The
      governing provision is Art. 69 of the RPC.