I have a 60" Panasonic Plasma TV that weighs 81 lbs. I want to hang it on the wall using a full-motion wall mount made to handle 175 lbs. The wall is drywall with wood studs. I plan on using the 4 lag bolts provided on two studs. I don't know the size of the lag bolts. The Instructions say to drill 3.5" pilot holes using a .25" bit. So, my guess the lag bolts are slightly bigger like 3/8". The problem I have is with the wood studs. There is one at the center of the wall. To the right, the next one is 12-13" apart (center to center). To the left, the next one is 16" away. These are 2×4 studs.
The wall plate on the wall mount has many holes in the back for the lag bolts. Would it be safe to shift the mount off center so that the end result is the TV is centered to the wall (but not the studs).
If it is not safe, would it load be easier to the studs on 13" apart or 16" apart?
If I can do option 1 but have to give up extending out the TV, I am ok with that.
UPDATE:
Thanks for all the input so far. The TV mount has 2 arms that attach the wall mount plate to the tv mount plate (they come together like a "V") but they cannot slide or adjust. Here is a link to the TV mount, product 12280 on monoprice. You can also some of it on the box in my pictures. http://www.monoprice.com/product?c_id=109&cp_id=10828&cs_id=1082821&p_id=12280&seq=1&format=2
I want to use 2 studs (and 4 lag bolts) but do not want to add any new boards behind or on the drywall.
These two pictures represent the options I am considering. 
As you can see, with Option 1 (red arrows) the TV will only be 3" off center to the Center Stud but it leaves 8" of the wall mount unsupported. Would this be an issue when I pull the TV out? Would strap toggles be necessary on the left side of wall mount?
Option 2 (blue arrows) looks for secure to me, but is further from center so I would only consider it if Option 1 is not safe. Thanks!
Best Answer
Measure the side to side of the back plate. I believe that most manufacturer's will have the plate long enough to span 2 wall studs. (BTW: most wall framing is established at 16 inches on center or 14 1/2 inches in between 2 wall studs). If your plat measures at least 16 inches install it on the 2 studs closest to the center of the wall. Some TV wall mounts have 3 axis' of adjustment: one axis allows you to swivel the TV side to side. This makes it easier to orient the TV on the center if the mounting plate was not. Also, it may be possible, depending on the mounting plate type, to offset the bracket that attaches to the back of the TV so that when it is hung on the wall mounting plate it is closer to room center.