The lens of the JVC G15 is aligned with the top of the screen when it is inverted and ceiling mounted. The specifications for the G15 state that the lens is 50% off-axis. The specifications for the lens on the SX-21 state that the lens is 40% off-set. Is the lens on the SX-21 aligned 10% below the top of the screen? 10% above the top of the screen?