On my bike that has OEM parts, when I have the breakerpoints exactly where they are supposed to be, they are both in the middle of the adjusting range. Then, after I have done the timing, also the plates are both in the middle of the adjusting range. I'm not saying this goes for any CB500/550, but these are my results with original TEC parts. To adjust the timing, I only have to readjust the breakerpoints gap and all is fine.