It is normal.

BMW defines anything up to 1 litre per 1600 km as normal. If you went 4000 km there is nothing unusual about adding a litre of oil. You also don't know for sure that the oil was full topped off when the service was done, it could have been down a bit when they finished. Check it every 1000 km for the next 5000 km or so and see what the true consumption is. Keep records so that you have information for the dealer if you get into a discussion with them.

In the meantime, don't worry and just enjoy the car.

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue