Hi jt,
Yes, you are right. I have read of this procedure. It is a means of last resort. And, yes, it can be overdone. You are supposed to press gently, but firmly (whatever that is?) until you can feel it bottom out, then stop, and tighten up the lock nut.
Normally, of course, it is done with the engine off, preferably with the valves correctly adjusted, and with the #1 piston 15 degrees past the TDC from your points/ignition plate.
I would be a little spooked about "feeling" that bottom out part.
~ ~ ~ jaknight ~ ~ ~