I guess I am not still sure! I am only concerned with "external" audits as I am a single biller for a single provider.
What "documentation" besides EOBs, patient charts and Superbills do we need to keep and for how long?
If there are entry errors (Dx code or CPT codes diff in billing software vs. Superbill) are they scrutinized?
Are clinicals scrutinized for correct E/M levels? what info can physician enter in the clinicals to make sure he is in compliance?

Etc.