Milano Red does change its apparent shade according to ambient lighting conditions. In the shade (or if dirty) it does look quite dark. In brighter light it looks noticeably lighter whilst in sunshine it positively bursts into life with an almost orange tint.
Although it is a no-cost option, apparently it's technology is quite complex, the base coat, top coat and clear coat all contributing to the final perceived appearance. Where there is no clearcoat, such as inside the door shuts, the colour looks positively pink.
I have seen one or two red GDs which had faded panels, but these may have been areas which had been re-sprayed rather than factory paintwork.