Not more expensive at all. Example; December of 2016 I bought a second Typhoon H from CarolinaDronze. Two things I wanted changed before it shipped were the lens on the CGO-3 and the 2.4g aircraft antennas. So a PixAero 3.77 lens was installed in the new camera and 2.4g dipole antennas were installed on the bird at CarolinaDronz. The combination voided factory warranty for the system but the total cost was in the area of $1,300.00.
If you elect to buy a new camera and have a different lens installed then the price gets a lot closer to the E50 camera, but bear in mind the E-50 is not compatible with the H-480. To employ the E-50 you must first buy a 520, which is a heck of a lot more expensive than a Typhoon H.
As the E-50 is still a 12Mpxl camera the only real difference between it and the CGO-3 is focal length. The E-50 lens focal length is the same, if not the same, as a Peau 8.25mm lens. The sensor and processor is likely the same as the CGO-3, just installed in a gimbal altered just enough to mitigate the difference in weight of the new lens. Not making the new cameras, or at least one of them, backwards compatible was an extremely bad marketing/design error.