Valve adjustment issues., Weird... Options

[Bob L.]

I have been cleaning a new to me engine to put in my '73. It's a '76 2.0 D-jet- stock valve train. After re-installing the rocker arms I went around and adjusted the valves using Cap'n Krusties' Rocking method and it seemed to be going fine. After getting all valves done I decided to check them all again. This is where it gets weird. While checking one rocker/valve I notice that another one seems to be looser than it was when I set it. I understand how it could get tighter as the cam rotates and closes the valve.
According to the rocking method the Rocker being adjusted is on the backside of the cam (opposite the lobe) and therefor as loose as it should get.

So, why Can I measure a greater gap when It should only be able to get smaller? (IMG:style_emoticons/default/confused24.gif)
Apparently I'm not the only one who has run into this.

Also, I get different gap readings when using the piston at TDC method. Some are the same, some loose or tight.

This is my first time working on the rockers/valves, FWIW.
Let the learning begin(continue)!