If you candle them before setting it will be fairly obvious if there is a problem with the air cell, it should be fixed at the flat end of the egg (or there abouts), if you turn it under a candler and it constantly floats to the top it means its detached.
There are also saddled air cells due to being stored on their sides too long, thats when the air cel is wonky aroiund the diameter of the egg instead of being a smooth line.
There are quite a few threads about this in the forum, i recieved a lot of advice in May just gone as my shipped aruacana eggs were in awful condition on arrival, i opted to set them upright during incubation and had a good result, it was my first time dealing with shipped eggs so i wouldnt emphatically state that its the way forward, i dont know wether anyone else can offer their opinion?????