WARNING: This page is about a different car, the 2010 BMW M5, 2009 BMW M5, and 2008 BMW M5. However, it is still accessible from the selected car via links, so may be relevant.
A/C SYSTEM AND OIL QUANTITY - TECHNICAL DATA SPECIFICATION
The data on the A/C compressor rating plate are definitive Refrigerant oil Fill quantity R 134a Sourcing reference in Parts and Accessories Catalogue