Mix Synthetic oils?

[motofranz]

I am using BMW Synthetic oil in my RT .
Would it matter if I mixed another brand of Synthetic oil
to top up the oil level ?
( Prolly just a half pint )
Are all Synthetic oils compatable?
My oil level is at the bottom of the bullseye glass.

[bearsfolks]

Here's how it was explained to me: the largest buyer of lubricants is the U.S. military. They buy from hundreds of vendors and use the products in hundreds of ways. To be sure of compatibility they write standards that are voluntarily followed by everyone interested in some government money.It is safe to mix brands, just look for the same API use symbols.