In my experience, if I downgraded from A16 to A11 directly, artifacts still occurred. I had to downgrade to A03 to reset something...unsure what. Then I could upgrade to A11 and artifacts are gone. In some Dell, I'll get an error if I jump from one BIOS version to another, stating a prerequisite version in between before I can upgrade to that specific version, if that makes any sense.
So if you don't encounter any artifacts from A16 to A11, then you don't need to worry about it.