Hmmm, OK.I meant the number of miles between the computer telling me to add a quart. Perhaps I was a bit loose with my word choices.
How about this: Drain all oil out and measure how much you actually have inside the engine. Your oil sensor might be giving you the wrong data.
Did you check whether you have any codes? Did you replace the water pump at all or is it original in? On N52 water pump and oil sensor go through the same BUS, if the water pump starts to slowly fail, it will mess up the oil sensor too.