Probably okay to bill just about all admissions as Level 3 as long as your H&P documentation has all the info that's needed for a level 3 H&P. Level 3 is the most commonly billed for inpatient H&Ps, and new admissions usually do take some effort.
Would be more careful about billing all your follow-up progress notes as level 3 since a good amount of them are level 2 (when compared to other hospitalists' billing). Especially for patients who have been there for a week and are completely stable and you're barely changing your note from the previous day. However, even for a completely stable patient that you're not changing much medically, you can still bill on time. For example you spent more than 35 minutes talking with the patient/family or talking with case manager about their discharge planning, you can still bill a level 3 even if you don't end up doing any high complexity medical decision making on that patient that day.
However, audits get are not usually triggered by just looking at any single note, but usually when your distribution of billing is much higher than the average for your practice or location.