Medicare split visits

I have a question I am hoping some of you can share your experience with. When a Medicare pt comes in for a PE and there is a second level of service that also qualifies to bill then Medicare as we all know allows us to carve out the portion of the E&M and pap/pelvic/breast exam from the PE. The question I have is when there is a secondary payor-it muddies things - or seems to at least.

We are trying to decide whether to do the carve out before sending it out the door or carve out before it goes to the patient. How do the rest of you flag this in your PM systems so it does not slip by and get transferred by an electronic remit out to the patient prior to carving. COB - who rules in this case..Pri or Sec? Is there any issue with sending to sec with the carved out price? I almost think you would have to or you could have issues with the balance...

I hope this makes sense.....and that someone can shed some light on their process as well.

Thanks in advance!