Our gym has 2 boys who are Level 7. Their routines seem fairly similar to 6 but with a different vault and giants on the High Bar. None of our 7's are Division 1. Since we had a lot of 6's that got trapped in the age group change last year and weren't ready for Level 8, our gym put them all in JD, so they could start learning the Level 8 skills and putting them in their routines as they got them. The boys who did 7 were the younger boys (9 and 10). If you were a Level 6, 10 or older, and going to be competing as at least an 11, you did JD. They also put some kids in JD2, who didn't have any bonuses in Level 6. It didn't seem like many boys were Level 7 at the meets. From what I have heard, a Level 7 routine with all the bonuses in pretty similar to a Level 8 routine, but I don't know. Our gym is also big on trying to get them into optionals and has a large JD program, which they then use to feed into Levels 9 and 10. - We have only a handful of 8's as well. As for practice, the 8's and JD's practice together for the same hours, and work on getting the same skills. The 7's and 6's practice together with the JD2's. The biggest difference I saw was that all JD's no matter the age compete with the handles on PH, which I think is great practice for the upper levels.
Anecdotally, there was one boy my son's age in Level 6, who was a little better than my kid on certain events, but not as good on others, but he was an amazing tumbler. The coach decided to put him in Level 8, and he ended up having a pretty bad season, finishing in the bottom tier every meet. We left that gym, and at evaluation our new coach said my son didn't yet have Level 8 skills. I agreed, so we decided to JD him and by the end of the year, he has solid Level 8 skills. A much kinder approach than putting a kid in above his level, who is used to winning and then end up being close to the bottom of every meet. The only downside for my son in JD, was that he often finished behind kids who were doing much easier routines. So, our mantra for this year was SKILLS, SKILLS, SKILLS, rather than places. I think we got lucky joining a gym where there is such a big JD team (One of our coaches is the Regional JD Rep) so they are committed to the program and use it as a pipeline rather than a rec league, so once the kids get to 9/10 they have a good shot at making Nationals.
But since our gym has over 50 boys, there are always practices running, so you might end up practicing with any assortment of boys, which make Summer practice a delight, because if you can't make the 9-1 practice, you can do the 5-9.