The compressor comes with the right amount of oil for the compressor, not more to compensate for anything in the rest of the system. If no flushing or changing anything in the system that contains oil happens then the level will be fine.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)