Only what the manufacturer requires is relevant. If an oil meets the specifications in the manual, you can use it and if you ever have a problem and can document your oil changes, SOA will have to repair the problem under the terms of the warranty.
It's really as simple as that.
The issue isn't whether an oil will work or even whether an oil will be absolutely brilliant in the motor for a given time. The issue is only the requirements stated in the warranty booklet.