Is there now a special definition to the 10th frame? I was not aware of that.
The frame does not, as near as I can tell, continue. They are not called "fill" balls for nothing. You're "fulflling" the 10th frame in which you are entitled to the count garnered by the fall of 1 or 2 more balls, as the case may be. It is not the "11"th frame, which does not truly exist. You are just finding out how many extra pins you will get as a bonus for your mark in the 10th frame, the last "frame" of the game.
The 10th frame is "special", or at least different, because you have the potential for 3 deliveries instead of just 2. So a frame is not a frame. If you do a search in the rules book, you'll not get a hit on "fill". It's simply not there.
I understand the rationale for artificially finishing the game, for the purposes of "clean", after the first 2 deliveries in the 10th. The scoring designers wanted to make all frames equal in determining clean. Again, I get that. In competition, you accept the definition, go with it, and congratulate anyone who gets an award or makes money accomplishing it. I always have and always will.
But the fact is that the game isn't over after making a strike with the first delivery in the 10th. The game has 2 deliveries left. Those deliveries conclude with either a mark or an open. If you can't knock down all 10 pins with those final 2 deliveries, you really haven't reached the finish line without a blemish. Hopefully, the most extreme example of finishing with 2 gutter balls and being considered clean should drive that point home.
To those who addressed rule 2g, thanks for the clarification. In reading, it's not 100% clear if it applies to any 2 consecutive deliveries in the 10th, or just to the first two. After all this discussion, I'm guessing it's just the first two.