Don't pay any attention to the drop from 100% to 90%. Its meaningless because the phone doesn't report true charge once it hits 100%. Android engineers have confirmed it and here's a blog post i wrote explaining it.
Droids 'n Things: My Battery life
In it are links to an article where the actual drain was measured as compared to displayed as well as quotes from an android engineer confirming it.
If you want to measure your idle drain start it from 90% or less and see how far it drops over night..