I could send you one of my ipods if you want to test one, as it would be invaluable to me. I have 2 set up identically for taping (basically, one for the first set - one for the second, because of the battery limitations)
I'm guessing the +10 setting is "Low" and the +30 is the "High", but what is the 0db setting?
Also, did you listen to the sample? This was actually recorder on "High", with the volume down at about 1/3.