The SOS advance that can be attained from the Arcade shot is collected only if you have Flynn Arcade lit. To light it you have to shoot the right outer loop.
In SOS you don't use that much because you start SOS in the Flynn Arcade, so it starts unlit.
But it is very useful in those days that you simply can't shoot gem and you don't know why.
Go for it, the new code is really awesome. And the fact that now you can get an extra ball worths it all.

That is correct.

It is very useful for for the light cycles for example, where you need to shoot them all and you can get a free gem or quorra shot.. but you still have to shoot the rest.

Yep. You only use the free shot for gem if you are having a hard time getting it. The right orbit is way too difficult.. not as difficult as gem though.

No. You get the same score.

guess i was wrong
..but all the rest i am sure i was right

Yep, agree.
This is also my point of view. And the new code is way too good to keep the old one.
Camon, a disc multiball restart with new sounds? New dmd animations? The possibility to change clu lights in sos? The extra ball feature?
Way better than the old one (was perfect already).