Weird thing when hand torquing new Uninstalled Spark Plugs vs Reinstalling it

[taiyou]

Don't bother reading my thread below; I will make my question simple:
Why does it only take 11 and 1/2 turn to finger tight NEW Uninstalled Plug vs 12 turns on used/already installed Plug? I tested on all 4 of the plugs to make sure it wasn't a fluke.




I know it's not difficult to change spark plugs, but it took me 3 hours and I still don't think it's at the right torque, even though it's running fine. I don't have a torque wrench, and I'm using NGK BKR5E-11 V-Power Plug(w/gasket) on KA24DE.
Reason why it took so long is that I discovered something new to myself, and I cannot find any threads about this so here it goes:

I finger-tightened the newly FRESH UNINSTALLED plug, then 1/2 turn hand torque was very smooth(felt like crushing the oil drain plug crush washer).
Then I took it out for some reason and finger-tightened but the 2nd time I tried to 1/2 turn, it was pretty stiff.

So on my 2nd new UNINSTALLED plug, I counted how many turns it takes to get it finger-tight. It was 11 and 1/2 turn. Then I did 1/2 turn hand torque; took it out, and it took 12 turns to get it finger tight the 2nd time! If you do the math, 12 turns should be right because you add 11.5 and .5=12, but this confuses me now!

So I'm not really sure if you still have to hand torque 1/2 turn on already installed/used plug?? If I were to use Torque wrench the 2nd time, wouldn't it double the torque spec? I hope this makes sense. Please help me out.