Lz mm. 一个面试邀请也没有 is actually not a bad news at all, since you only have 1 y W/E. Longer W/E will not only help you go to better school, it will also help you find a good job after MBA. Frankly, two year experiences may be too short.
You must think this way: If you were accepted to a 2nd/3br-tier, you spend a lot money; then you cannot find a job in US to repay your MBA expense.
I live in the states, important emails related to admission process are always sent out during biz hours. unimportant emails related to other school events/news could be sent out any time. But that is just my personal experience.