That section I referenced does not have application just to the hospital environment. It is for any outpatient service--including surgeries and/or clinic visits.
Perhaps I am misunderstanding your objective; I thought you were asking where it was printed that the primary reason for the encounter be listed as "first listed" (e.g., Primary) diagnosis. To my knowledge, there is no restriction written anywhere that says the presenting problem must be the primary diagnosis.
For instance, a patient may present with a chief complaint of "sore throat." The physician examines the patient, determines through a series of lab tests and a culture that the patient actually has Streptococcal tonsillitis. In that case, you assign the appropriate code for strep tonsillitis, in lieu of a code for sore throat, as the symptom (sore throat) is integral to the disease process.
In the OP realm, diagnoses are coded based on certainty, rather than IP rules. Regardless of what your presenting problem/chief complaint, you would code to the actual reason for the encounter--which very well may be different from your presenting problem.
I didn't mean to confuse you. Perhaps this will help.
If you're asking something different than what I infer, maybe someone else can chime in and offer insight.
Good luck.