I am confused by 3.3.6 and 3.3.7 requirements for peening time. Per 3.3.6, parts shall be shot peened "using the same...time...as used on the test strip." On the other hand, per 3.3.7, "parts...shall be peened to complete visual coverage." It seems to be common knowledge that aluminum alloys reach full coverage faster than steel, so these requirements appear to conflict. We have been specifying that the coverage requirement rules (i.e., peening times on aluminum parts can be lower than T1). But how will an auditor view this?

John,
You are exactly right, the specification incorrectly refers to coverage based upon the Almen strip. This is why the Surface Enhancement Division of SAE revised SAE J443 regarding the Almen strip to be used only for intensity and then the committee created a separate document SAE J2277 for Shot Peening Coverage. This clearly explains the methods to be used to establish coverage on your part.
I expect that AMS-S-13165 will be revised to address this inconsistency. Contact me if you wish to participate in this project.