This is normal. Happened to me as well just after my 1200 mile service. In fact, I was even getting oil level warning messages.
My SA explained to me that they're still "getting to know" this engine and that since there's no physical dipstick, they're afraid of overfilling the oil reservoir. The oil filter alone can absorb nearly a quart of oil. I liked the fact that they erred on the side of caution. Not saying the situation is acceptable, but am saying that it's a known issue and nothing you should be worried about. Just top it up.
My SA gave me a cool BMW-branded zippered pouch that contains a quart of oil, a paper funnel and some other goodies. It's got velcro strips on the back so I can affix it to the interior of my trunk. You should ask for one so you're not caught off-guard after your next service (15,000 miles).