this "supposed" test is not just to test the housing. It is to test the axle assembly as a whole. After the test, the parts are removed, inspected many ways in the metrology lab including CMM and other analysis
Absolutely irrelevant.
Where exactly it was focused is irrelevant here.
Yes, for how long? Lets not pretend this is anything significant either please.sometimes, the axle is put on a vehicle and ran through a battery of on the vehicle testing.
By gosh you are full of excuses.They don't just see if the axle housing is bent and throw it away. These tests cost hundreds of thousands of dollars by the time everything is complete.