Most of LCD monitors have a response time, so I think it definitely affects the lag test, but I also think these are exactly the 16ms. you had in the test.
I think your test is properly configured (or at least I can't think a better way to do

So try to check the lag playing a shmup with a PS2 wired controller (I think the touhou series would be excellent) and tell us how does it feel to you.

Thanks once again.