Zurich STARS
 

Could anyone explain to me:
When flying into ZRH on BLM3E (Basle-Mulhouse 3E) arrival in the descent planning it sates pilot expected to be FL200A at 9 Dme before BLM, FL 150A at BLM and FL120A at ZH675, I am just wondering what the reason is behind this and when do ATC expect us to comply with this as, if you plan these heights and get a no delay approach (very rare) approach it leaves you quite high.
I must say that in a few years of operating into ZRH I have never heard of ATC expecting us to achieve these heights.
Any thoughts from fellow colleagues?
Regards, Bokkie449.