Clarification on SpO2 method preferences

LOINC recommends use of 59408-5 rather than HITSP’s 2710-2 for Vitals, and while I’m not familiar with a procedure for attaching an oximeter “where arterial blood surges into the capillaries”, it’s possible that the differential calculation infers saturation for the “new” blood. So far, so good. Less clear is why, given a general consensus that methodless concepts are preferable, the recommended code still includes the oximetry method.