Those 9 small lugs are why I had my gunsmith laboriously lap all 9 into contact. It was a chore, and he made me pay for it, but I don't regret the expense at all...especially not now.
Not to say you may not have gotten what you paid for, but it is a physical impossibility to have all nine lugs touching equally.
When two or more surfaces reside in parallel planes, there can only be one primary locator, or one lug or pair of lugs. The other lugs will simply be the secondary, or otherwise known as along for the ride.
It's just the math and engineering of it all, nothing more.
