BUG in new "master volume" control not consistent using keyboard

FM 5.0b55 – using my Apple Extended Keyboard, pressing the “-” key and “+” key on the NUMERIC keypad area results in a decrease and increase in volume. Using the “-” key on the numbers row (to the right of the “0” character) results in a decrease in volume. BUT – using the “+” key (to the right of the “-” key) DOES NOT increase the volume. Can this be confirmed?