do you have that TV mounting system like you see in motels that are actually on the wall with a plate and it swivels and turns?
You have a very good question here. First if its the one described above and a 27 incher, you do have some weight issues and I think that one steel stud might not be able to carry this load and eventually bow or buldge through.
If this is the case, I would consider getting a 1 x 12 in oak and straddle at least two metal studs and then fasten this system in the middle of both. This way you are using two studs and the load is shared, but then I am not sure this will hold.
I think that you would have this same issue even with wooden studs. 27 incher is pretty heavy.