The smooth transition idea doesn't hold much water with me either.

Lets use 6k rpm example
So thats 100 revolutions per second - not even firing on every one of those.
Pulse widths in modern ignition and fuel systems are down to .001 ms resolutions. I dont' know the average discharge time for a spark plug but I think my dwell is in the 8ms range on mine. The motor could care less from one spark event to the next.

For those with 1bar sd tunes... seriously how much time does it see 80-95 kpa when you floor it?
Run what timing your motor likes out of boost - run whats safe while in boost. I'm still running 30+ degrees at low boost because my little 70 frequently sees boost while doing light throttle passing and accelerating. Mostly under 5psi - but it just runs better with the extra timing. Best power? Dunno, but feels better. I don't make crap for power until 10+ psi and up there is where I start to pull my timing.