There are some factors that might be at work, which could explain the higher draw for 20 seconds (i.e. interior lights time-out).
I'm confused by your numbers though... 1.10 milliamps is not a very big current draw, but 1100 is! Could you clarify? Seems you're saying the draw is 1.1 mA, then you say "which is 1100mA" (that's over 1 amp!). Which is it? Then you say it should draw .1mA (100mA). Is it .1, or 100? It's just confusing the way you wrote it...
I would assume SOME current draw, even with everything off. Some stuff still gets 12v, like the clock in your radio. Even though the display is off, it needs to be powered to keep time. Having said that, the draw from items while OFF should be minimal... a few milliamps, to possibly a hundred or so. For reference - a single LED usually draws around 20 mA. A car battery could power that LED (literally) for years without draining the battery. | 
