Evil, Harmony, Perspectivism

Leibniz seems to not recognize a significant discrepancy between his proposition that "This is the best of all possible worlds", and his concept of Pre-Established Harmony.  For, according to the former, Evil is actual, but necessary to the maximation of Good, while according to the latter, the positing of its existence is only an expression of an inadequate understanding of the whole.  Correspondingly, Voltaire's criticism is of the former necessity, e. g. the Lisbon earthquake, while a Marxist can detect in the latter analysis a prototypical ideological suppression of the actuality of exploitation.  Furthermore, Leibniz does not seem to recognize that an improvement of the understanding can have implications beyond itself.  For example, in his Perspectivism is entailed the possibility of a modification of actual conduct, i. e. from the treatment of others as antagonists, to that of them as interdependent with one.  That possibility thus refutes the concept of Pre-Established Harmony, because it entails the possibility of a hitherto unestablished Harmony.