sinus surgery PO being billed with OV and debridement/endoscopy codes

- Sinus surgery is 0 Global days , but here is a concern we have. A very common surgery in our practice would be a septoplasty (30520), inferior turbinate submucous resection( 30140 )and Full FESS( all Sinus) (31276,31255,31267,31288) . So the first part of this Question is this- If you bill A surgery that has 90 day global like 30520 and 30140 with Surgery that has Zero global Sinus surgery (same operative session) , Does the 90 day global trump the Zero day Global? I read an article recently and it stated that if you mix global day surgeries that the higher global is in place for that Surgery. Is this True?

Part 2 - Sinus surgery follow up visits- Our doctors do endoscopy debridement’s following Sinus Surgeries, CPT® code 31237, my concern is this is an expected procedure after Sinus Surgery (debridement’s), The doctors also want to bill an Office visit with this 31237. , It is believed that because the Sinus Surgery has Zero Global days that this is allowed. Is this True? Can you bill both(office visit and debridement) since Sinus Surgery has Zero Global days, Or should we only bill the follow up debridement’s after Sinus Surgery? I do realize that if they come in for a post operative debridement following Sinus Surgery and the patient has a new problem or concern that needs to be addressed,( unrelated to the sinus surgery) then an office visit would be Justified and acceptable to bill . Please clarify the rules on this.

Any documentation and back up material would be great to be able to share with my doctors