Hann, while it is certainly ok to use an off/center or skewed approach to singing into a mic, it's important to understand near-field audio wave characteristics(in this case the ones coming from your mouth). I could go into a long answer to all this, but it's very easy to just experiment with it. As you probably know through experience, the closer to the mic diaphragm, the more lows will be mixed in with the highs. When coming out of the mouth, the audio's low frequencies are quite directional, and moving that direction away from the mic's diaphragm's center, will effective change the "eq" mix of your vocal reaching the mic's diaphragm. this doesn't mean it's not going to sound as good. Just know that it will have that affect on the wave hitting the mic's diaphragm. I use this "skewed" technique in some recording situations.
Russ from Coral Springs, Fl