I really don't know. I haven't adjusted mine yet. I would expect your assumption is right though, as that would make sense.
I went right through the Workshop Manual but didn't find anything about setting the timing, other then that initially it should be 6° BTDC for premium fuel and 3° BTDC for regular fuel. Optimum setting is supposed to be done by road test. That would be fun. I wouldn't like to be the guy with his hand down through the gap, trying to turn the distributor slightly while screaming "Hows that now?" to the driver over the noisy engine while being zapped off the plug leads.
When it's time to do mine, I think I'll be the driver.
Greg.