Wheel Alignment Advice

[mtech8]

So I've gone through two sets of tires on my car. Both times the alignment was done by BMW and both times the inside wore out heavily while the middle and outside seemed to still have life.

Dealer indicates that this is because sandbags are placed in the car to simulate passengers and that this was the only way BMW would do alignments.

Is there anything I can ask for to have an alignment done where the wear would be more even?

What is the benefit of setting up the wheels that way rather than completely level? Assuming normal driving (not racing).