What I mean is this:
E70 2006 - SUV X5
E85 2003 - Roadster Z4 E86 2005 - Coupe Z4
E87 2003 - 5 Door Hatchback 116i, 118i, 118d, 1201, 120d, 130i
Cars with higher E numbers coming to market before those with lower E numbers.
My only thought was that the E number must be issued when the model is first originated, before all the development work to get it to market. Therefore if there are multiple groups working on more than one model (which there undoubtedly are), you could in theory have this occur if one vehicle takes less time to develop than another.
However, the original 1er is the E87, which came to market in 2003. The second generation X5 though is the E70 and that was only launched in 2006. You can't tell me that the X5 took a whole three years longer (at least) than the 1er to develop?
What's the deal?
Thinking again more deeply, perhaps if a car has a longer life cycle than another you might get this happen, but you wouldn't design a car and then shelve it for 3 years until the old one's wound down - your 'new' model would be obsolete before it launched