Your Friend Is Discussing Oscillators with You and Makes the Statement

Your friend is discussing oscillators with you and makes the statement "Pendulum clocks are harmonic oscillators and work exactly like masses on springs that bounce when something is placed on them - the heavier the object the slower the oscillation (smaller period). They take kinetic energy and potential energy and switch them back and forth while keeping the sum of the two constant." Please identify three points which your friend got incorrect.