Only for small poppers and ones where you don't need to plunge too deep since the tit of the bit is at the angle of the face, not parallel to the center hole.
If you plunge cut centered on the hole then cut a slant you get a thicker lip at the bottom of the plug. If you plan to do it this way you need to plunge off center about 1/8" towards the bottom of the plug.
Even then, if you plunge cut a popper face you end up with a deep cup which you often don't want.
This thread will help if you plan to do it that way.
http://striped-bass.com/Stripertalk/...ht=blue+streak