My checks are finally cashed..
I dropped my package (I-130, I-485) on 1st Oct in the drop box of San Jose office. My checks got finally cashed on 22nd Nov. I haven't received any notice yet, i'm still waiting.
Earlier in late October, I was curious and impatient and took an infopass appointment for Nov 9th and met with an officer. He told me that there is a backlog of 2 months in opening the new packages, after that I was little relaxed and now my process is moving.
So, don't worry, packages normally don't get lost, they just don't get open at times.