I know that my old 1998 A4 only flashes the Glow Plug light to indicate a brake light buld has blown. It does not detect any other bulbs. I don't have DIS.
Maybe someone with DIS can post what bulbs the system monitors.
My DIS tells me bulbs are blown when they're not.
It should tell you about all external bulbs, brake lights, headlights & side lights, also which side.