Milton,
I questioned that too. I'm using a Synchro Spark unit on my Homie 25. I read the directions, (with lots of typos) and they alluded to set the timing at 28 deg for both standard and Synchro.
I set my timing at 0 on the Syncro and as the RPM builds it advances timing to 28 near full throttle. The engine runs great there!
I sure as hell didn't want it fully advanced when I was flipping it!
I'm going to confirm it with a timing light the next time I run it, but at 0 deg static, the Syncro Spark works fine for me.
After all, the job of the Synchro unit is to give
0 deg at idle for smoothe idle and kick free starting, and 28 deg at the top end for max power.
Barry