Hi Joshwa,
Yes, you are right. On ranktracker reports we search the URL of the report inside the Organic and on Maps pack.
If is_carouselfallbackmode is true, we will search the URL/brand inside the Google Carousel too.
This affects only very specific reports types and normally it makes no difference. BUT if you want do rank tracking inside the carousel, you need set this as true.
Renan Gomes.