I have asked this question quite a few times here and BMW coding forums. The response that i got has been that the later 2010 engineering change was with the receiver and it's capabilities. The receiver has access to TPM sensors but unable to determine which wheel was low and hence the vague idrive status. However logic dictates that for the tpms system to just flash that a tire is low on pressure, it has to get some form of pressure reading from each wheel indicating that it's low (may it be tpm sensor or wheel rotation sensor). Hence it should just be a simple software change that makes the reciever system information available to the driver's idrive. Soo it's eithwr a move that saved BMW some programming costs or idk they wanted all x5 owners to learn how to check tire pressure the good old way lol.
BMW and Mercedes Build Beta Products!
Lexus build Release Candidate Products!
Why does this matter?
CAUSE EVERY TIME someone says Lexus has better build quality, one should consider what Toyota their Lexus Engine and chassis platform comes out of and how long that part has been tested in the real world!