I tried to update my Ipad 2 16 GB today and I get the message that the update takes 2.9 GB of storage and I only have 1.0 GB available. In looking at my usage on the Ipad, my music is taking 9.4 GB of storage. When I look at Itunes on my laptop, it says the same music is 4.89 GB. What am I missing? I really don't want to delete any of my music.