It really shouldn't affect your index much, if any. With a course hcp of 10-19, your ESC is 7 on any given hole. Unless you're the most wildly inconsistent 10 hcp in the world, you just don't have many 8's or higher to adjust down. Of those that you do have, fewer yet will be found in your low 10 of your last 20 scores. I'd be surprised if your index changes more than a tenth or two. Honestly, I wouldn't worry much about it and just post correctly going forward.