Charging a re-billing fee

I ran across a physician practice that has begun charging a "rebilling fee" beginning at 90 days. They clearly state on their patient statements that the rebilling fee will be charged on balances over 90 days. According to the administrator, this has been really effective in getting patients to pay earlier rather than watching their balance role across until it reaches the 120 day box.  It has also helped with balancing out what they might receive in the future when we finally do send a patient to collections (they include the rebilling fees along with the balance). Is anyone else doing this?

Again, remember my mantra – one statement only to the patient, then out goes the 10-day letter, and if the patient does not respond to the 10-day letter, then off to the collection agency.