Hello Mike and welcome to our family.
I can relate to the "tock" sound, I guess all our greys pretty much do the same sound, sort of like a click with their beak that means back off a little or not right now, you do learn quickly some of the ways they communicate their wishes to us.
Greys do tend to get more independent as they get older, sometimes they are just content to be near but not right on you, Josey will come over and sit by me sometimes while I am watching tv or looking over my shoulder as I type on the computer, of course she sometimes has to battle for my attention from the other two birds I have but usually as long as there is a little distance between them all is well.